endsWith in JavaScript

Question

How can I check if a string ends with a particular character in JavaScript   Example  I have a string   var str    mystring      I want to know if that string is ending with    How can I check it    Is there a endsWith   method in JavaScript  One solution I have is take the length of the string and get the last character and check it    Is this the best way or there is any other way

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7 years old post  but I was not able to understand top few posts  because they are complex  So  I wrote my own solution   function strEndsWith str  endwith        var lastIndex   url lastIndexOf endsWith       var result   false      if  lastIndex  gt  0  amp  amp   lastIndex    registerc  length     url length                result   true            return result

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String prototype endWith   function  a        var isExp   a constructor name      RegExp       val   this      if  isExp     false            a   escape a           val   escape val         else         a   a toString   replace              g           return eval       a       test val           example var str    Hello   alert str endWith  lo     alert str endWith  l o a

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function strEndsWith str suffix      var reguex  new RegExp suffix          if  str match reguex   null        return true     return false

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Its been many years for this question  Let me add an important update for the users who wants to use the most voted chakrit s answer    endsWith  functions is already added to JavaScript as part of ECMAScript 6  experimental technology   Refer it here  https   developer mozilla org en docs Web JavaScript Reference Global Objects String endsWith  Hence it is highly recommended to add check for the existence of native implementation as mentioned in the answer

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Unfortunately not  if   mystring   substr -1

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After all those long tally of answers  i found this piece of code simple and easy to understand   function end str  target      return str substr -target length     target

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For coffeescript  String  endsWith    suffix  - gt    -1     indexOf suffix   length - suffix length

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Unfortunately not  if   mystring   substr -1

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return this lastIndexOf str    str length    this length    does not work in the case where original string length is one less than search string length and the search string is not found   lastIndexOf returns -1  then you add search string length and you are left with the original string s length   A possible fix is  return this length  gt   str length  amp  amp  this lastIndexOf str    str length    this length

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Come on  this is the correct endsWith implementation   String prototype endsWith   function  s      return this length  gt   s length  amp  amp  this substr this length - s length     s      using lastIndexOf just creates unnecessary CPU loops if there is no match

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This version avoids creating a substring  and doesn t use regular expressions  some regex answers here will work  others are broken    String prototype endsWith   function str        var lastIndex   this lastIndexOf str       return  lastIndex     -1   amp  amp   lastIndex   str length     this length       If performance is important to you  it would be worth testing whether lastIndexOf is actually faster than creating a substring or not   It may well depend on the JS engine you re using     It may well be faster in the matching case  and when the string is small - but when the string is huge it needs to look back through the whole thing even though we don t really care     For checking a single character  finding the length and then using charAt is probably the best way

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all of them are very useful examples  Adding String prototype endsWith   function str  will help us to simply call the method to check if our string ends with it or not  well regexp will also do it   I found a better solution than mine  Thanks every one

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I just learned about this string library   http   stringjs com   Include the js file and then use the S variable like this   S  hi there   endsWith  hi there     It can also be used in NodeJS by installing it   npm install string   Then requiring it as the S variable   var S   require  string      The web page also has links to alternate string libraries  if this one doesn t take your fancy

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function strEndsWith str suffix      var reguex  new RegExp suffix          if  str match reguex   null        return true     return false

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7 years old post  but I was not able to understand top few posts  because they are complex  So  I wrote my own solution   function strEndsWith str  endwith        var lastIndex   url lastIndexOf endsWith       var result   false      if  lastIndex  gt  0  amp  amp   lastIndex    registerc  length     url length                result   true            return result

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all of them are very useful examples  Adding String prototype endsWith   function str  will help us to simply call the method to check if our string ends with it or not  well regexp will also do it   I found a better solution than mine  Thanks every one

User · Answer

if you dont want to use lasIndexOf or substr then why not just look at the string in its natural state  ie  an array   String prototype endsWith   function suffix        if  this this length - 1     suffix  return true      return false      or as a standalone function  function strEndsWith str suffix        if  str str length - 1     suffix  return true      return false

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String prototype endsWith   function str    return  this match str       str    String prototype startsWith   function str    return  this match     str   str     I hope this helps  var myStr        Earth is a beautiful planet       var myStr2   myStr trim             Earth is a beautiful planet      if  myStr2 startsWith    Earth         returns TRUE  if  myStr2 endsWith    planet         returns TRUE  if  myStr startsWith    Earth          returns FALSE due to the leading spaces     if  myStr endsWith    planet          returns FALSE due to trailing spaces      the traditional way   function strStartsWith str  prefix        return str indexOf prefix      0     function strEndsWith str  suffix        return str match suffix       suffix

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So many things for such a small problem  just use this Regular Expression   x000D   x000D  var str    mystring    x000D  var regex           x000D   x000D  if  regex test str    x000D      if it has a trailing     x000D    x000D   x000D   x000D

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all of them are very useful examples  Adding String prototype endsWith   function str  will help us to simply call the method to check if our string ends with it or not  well regexp will also do it   I found a better solution than mine  Thanks every one

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Didn t see apporach with slice method  So i m just leave it here   function endsWith str  suffix        return str slice -suffix length      suffix

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This is the implementation of endsWith   String prototype endsWith   function  str      return  this length  gt   str length   amp  amp   this substr this length - str length      str

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If you re using lodash     endsWith  abc    c       true   If not using lodash  you can borrow from its source

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Unfortunately not  if   mystring   substr -1

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if typeof String prototype endsWith      function                    String prototype endsWith        Check if given string locate at the end of current string         param  string  substring substring to locate in the current string          param  number   position end the endsWith check at that position         return  boolean                 edition ECMA-262 6th Edition  15 5 4 23             String prototype endsWith   function substring  position            substring   String substring            var subLen   substring length   0           if   subLen  return true   Empty string          var strLen   this length           if  position     void 0  position   strLen          else position   position   0           if  position  lt  1  return false           var fromIndex    strLen  lt  position   strLen   position  - subLen           return  fromIndex  gt   0    subLen     -fromIndex               amp  amp                    position     0                    if position not at the and of the string  we can optimise search substring                     by checking first symbol of substring exists in search position in current string                    this charCodeAt fromIndex      substring charCodeAt 0   fast false                            amp  amp  this indexOf substring  fromIndex      fromIndex                      Benefits    This version is not just re-using indexOf  Greatest performance on long strings  Here is a speed test http   jsperf com starts-ends-with 4 Fully compatible with ecmascript specification  It passes the tests

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I don t know about you  but   var s    mystring    s length  gt   1  amp  amp  s s length - 1             will do the thing    Why regular expressions  Why messing with the prototype  substr  c mon

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Do not use regular expressions  They are slow even in fast languages  Just write a function that checks the end of a string  This library has nice examples  groundjs util js  Be careful adding a function to String prototype  This code has nice examples of how to do it  groundjs prototype js In general  this is a nice language-level library  groundjs You can also take a look at lodash

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So many things for such a small problem  just use this Regular Expression   x000D   x000D  var str    mystring    x000D  var regex           x000D   x000D  if  regex test str    x000D      if it has a trailing     x000D    x000D   x000D   x000D

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A way to future proof and or prevent overwriting of existing prototype would be test check to see if it has already been added to the String prototype  Here s my take on the non-regex highly rated version    if  typeof String endsWith      function         String prototype endsWith   function  suffix            return this indexOf suffix  this length - suffix length      -1

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I don t know about you  but   var s    mystring    s length  gt   1  amp  amp  s s length - 1             will do the thing    Why regular expressions  Why messing with the prototype  substr  c mon

User · Answer

For coffeescript  String  endsWith    suffix  - gt    -1     indexOf suffix   length - suffix length

User · Answer

Its been many years for this question  Let me add an important update for the users who wants to use the most voted chakrit s answer    endsWith  functions is already added to JavaScript as part of ECMAScript 6  experimental technology   Refer it here  https   developer mozilla org en docs Web JavaScript Reference Global Objects String endsWith  Hence it is highly recommended to add check for the existence of native implementation as mentioned in the answer

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function check str        var lastIndex   str lastIndexOf           return  lastIndex    -1   amp  amp   lastIndex      str length - 1

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Just another quick alternative that worked like a charm for me  using regex      Would be equivalent to      Hello World   endsWith  World     Hello World   match  World        null

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String prototype endWith   function  a        var isExp   a constructor name      RegExp       val   this      if  isExp     false            a   escape a           val   escape val         else         a   a toString   replace              g           return eval       a       test val           example var str    Hello   alert str endWith  lo     alert str endWith  l o a

User · Answer

Come on  this is the correct endsWith implementation   String prototype endsWith   function  s      return this length  gt   s length  amp  amp  this substr this length - s length     s      using lastIndexOf just creates unnecessary CPU loops if there is no match

User · Answer

Didn t see apporach with slice method  So i m just leave it here   function endsWith str  suffix        return str slice -suffix length      suffix

User · Answer

chakrit s accepted answer is a solid way to do it yourself  If  however  you re looking for a packaged solution  I recommend taking a look at underscore string  as  mlunoe pointed out  Using underscore string  the code would be   function endsWithHash str      return   str endsWith str

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Just another quick alternative that worked like a charm for me  using regex      Would be equivalent to      Hello World   endsWith  World     Hello World   match  World        null

User · Answer

This builds on  charkit s accepted answer allowing either an Array of strings  or string to passed in as an argument   if  typeof String prototype endsWith      undefined         String prototype endsWith   function suffix            if  typeof suffix      String                 return this indexOf suffix  this length - suffix length      -1           else if suffix instanceof Array               return   find suffix  function value                   console log value   this indexOf value  this length - value length      -1                    return this indexOf value  this length - value length      -1                 this                        This requires underscorejs - but can probably be adjusted to remove the underscore dependency

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return this lastIndexOf str    str length    this length    does not work in the case where original string length is one less than search string length and the search string is not found   lastIndexOf returns -1  then you add search string length and you are left with the original string s length   A possible fix is  return this length  gt   str length  amp  amp  this lastIndexOf str    str length    this length

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if    mystring    substr -1 1             -- Or --  if    mystring    match

User · Answer

This builds on  charkit s accepted answer allowing either an Array of strings  or string to passed in as an argument   if  typeof String prototype endsWith      undefined         String prototype endsWith   function suffix            if  typeof suffix      String                 return this indexOf suffix  this length - suffix length      -1           else if suffix instanceof Array               return   find suffix  function value                   console log value   this indexOf value  this length - value length      -1                    return this indexOf value  this length - value length      -1                 this                        This requires underscorejs - but can probably be adjusted to remove the underscore dependency

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This is the implementation of endsWith    String prototype endsWith   function  str      return this length    str length  amp  amp  this substr this length - str length     str

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test str    will work on all browsers  doesn t require monkey patching String  and doesn t require scanning the entire string as lastIndexOf does when there is no match   If you want to match a constant string that might contain regular expression special characters  such as      then you can use the following   function makeSuffixRegExp suffix  caseInsensitive      return new RegExp        String suffix  replace                      g       amp                 caseInsensitive    i             and then you can use it like this  makeSuffixRegExp  a complicated  suffix    test str

User · Answer

all of them are very useful examples  Adding String prototype endsWith   function str  will help us to simply call the method to check if our string ends with it or not  well regexp will also do it   I found a better solution than mine  Thanks every one

User · Answer

This version avoids creating a substring  and doesn t use regular expressions  some regex answers here will work  others are broken    String prototype endsWith   function str        var lastIndex   this lastIndexOf str       return  lastIndex     -1   amp  amp   lastIndex   str length     this length       If performance is important to you  it would be worth testing whether lastIndexOf is actually faster than creating a substring or not   It may well depend on the JS engine you re using     It may well be faster in the matching case  and when the string is small - but when the string is huge it needs to look back through the whole thing even though we don t really care     For checking a single character  finding the length and then using charAt is probably the best way

User · Answer

if    mystring    substr -1 1             -- Or --  if    mystring    match

User · Answer

If you re using lodash     endsWith  abc    c       true   If not using lodash  you can borrow from its source

User · Answer

Unfortunately not  if   mystring   substr -1

User · Answer

This is the implementation of endsWith    String prototype endsWith   function  str      return this length    str length  amp  amp  this substr this length - str length     str

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From developer mozilla org String prototype endsWith    Summary  The endsWith   method determines whether a string ends with the characters of another string  returning true or false as appropriate   Syntax  str endsWith searchString    position      Parameters   searchString   The characters to be searched for at the end of this string  position   Search within this string as if this string were only this long  defaults to this string s actual length  clamped within the range established by this string s length    Description  This method lets you determine whether or not a string ends with another string   Examples  var str    To be  or not to be  that is the question     alert  str endsWith  question           true alert  str endsWith  to be              false alert  str endsWith  to be   19         true   Specifications  ECMAScript Language Specification 6th Edition  ECMA-262   Browser compatibility

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This version avoids creating a substring  and doesn t use regular expressions  some regex answers here will work  others are broken    String prototype endsWith   function str        var lastIndex   this lastIndexOf str       return  lastIndex     -1   amp  amp   lastIndex   str length     this length       If performance is important to you  it would be worth testing whether lastIndexOf is actually faster than creating a substring or not   It may well depend on the JS engine you re using     It may well be faster in the matching case  and when the string is small - but when the string is huge it needs to look back through the whole thing even though we don t really care     For checking a single character  finding the length and then using charAt is probably the best way

User · Answer

chakrit s accepted answer is a solid way to do it yourself  If  however  you re looking for a packaged solution  I recommend taking a look at underscore string  as  mlunoe pointed out  Using underscore string  the code would be   function endsWithHash str      return   str endsWith str

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String prototype endsWith   function str    return  this match str       str    String prototype startsWith   function str    return  this match     str   str     I hope this helps  var myStr        Earth is a beautiful planet       var myStr2   myStr trim             Earth is a beautiful planet      if  myStr2 startsWith    Earth         returns TRUE  if  myStr2 endsWith    planet         returns TRUE  if  myStr startsWith    Earth          returns FALSE due to the leading spaces     if  myStr endsWith    planet          returns FALSE due to trailing spaces      the traditional way   function strStartsWith str  prefix        return str indexOf prefix      0     function strEndsWith str  suffix        return str match suffix       suffix

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test str    will work on all browsers  doesn t require monkey patching String  and doesn t require scanning the entire string as lastIndexOf does when there is no match   If you want to match a constant string that might contain regular expression special characters  such as      then you can use the following   function makeSuffixRegExp suffix  caseInsensitive      return new RegExp        String suffix  replace                      g       amp                 caseInsensitive    i             and then you can use it like this  makeSuffixRegExp  a complicated  suffix    test str

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This version avoids creating a substring  and doesn t use regular expressions  some regex answers here will work  others are broken    String prototype endsWith   function str        var lastIndex   this lastIndexOf str       return  lastIndex     -1   amp  amp   lastIndex   str length     this length       If performance is important to you  it would be worth testing whether lastIndexOf is actually faster than creating a substring or not   It may well depend on the JS engine you re using     It may well be faster in the matching case  and when the string is small - but when the string is huge it needs to look back through the whole thing even though we don t really care     For checking a single character  finding the length and then using charAt is probably the best way

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From developer mozilla org String prototype endsWith    Summary  The endsWith   method determines whether a string ends with the characters of another string  returning true or false as appropriate   Syntax  str endsWith searchString    position      Parameters   searchString   The characters to be searched for at the end of this string  position   Search within this string as if this string were only this long  defaults to this string s actual length  clamped within the range established by this string s length    Description  This method lets you determine whether or not a string ends with another string   Examples  var str    To be  or not to be  that is the question     alert  str endsWith  question           true alert  str endsWith  to be              false alert  str endsWith  to be   19         true   Specifications  ECMAScript Language Specification 6th Edition  ECMA-262   Browser compatibility

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function check str        var lastIndex   str lastIndexOf           return  lastIndex    -1   amp  amp   lastIndex      str length - 1

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if you dont want to use lasIndexOf or substr then why not just look at the string in its natural state  ie  an array   String prototype endsWith   function suffix        if  this this length - 1     suffix  return true      return false      or as a standalone function  function strEndsWith str suffix        if  str str length - 1     suffix  return true      return false

User · Answer

Do not use regular expressions  They are slow even in fast languages  Just write a function that checks the end of a string  This library has nice examples  groundjs util js  Be careful adding a function to String prototype  This code has nice examples of how to do it  groundjs prototype js In general  this is a nice language-level library  groundjs You can also take a look at lodash

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UPDATE  Nov 24th  2015   This answer is originally posted in the year 2010  SIX years back   so please take note of these insightful comments   Shauna -   Update for Googlers - Looks like ECMA6 adds this function  The MDN article also shows a polyfill  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects String endsWith   T J  Crowder -   Creating substrings isn t expensive on modern browsers  it may well have been in 2010 when this answer was posted  These days  the simple this substr -suffix length      suffix approach is fastest on Chrome  the same on IE11 as indexOf  and only 4  slower  fergetaboutit territory  on Firefox  jsperf com endswith-stackoverflow 14 And faster across the board when the result is false  jsperf com endswith-stackoverflow-when-false Of course  with ES6 adding endsWith  the point is moot   -    ORIGINAL ANSWER  I know this is a year old question    but I need this too and I need it to work cross-browser so    combining everyone s answer and comments and simplifying it a bit  String prototype endsWith   function suffix        return this indexOf suffix  this length - suffix length      -1       Doesn t create a substring Uses native indexOf function for fastest results Skip unnecessary comparisons using the second parameter of indexOf to skip ahead Works in Internet Explorer NO Regex complications   Also  if you don t like stuffing things in native data structure s prototypes  here s a standalone version  function endsWith str  suffix        return str indexOf suffix  str length - suffix length      -1      EDIT  As noted by  hamish in the comments  if you want to err on the safe side and check if an implementation has already been provided  you can just adds a typeof check like so  if  typeof String prototype endsWith      function         String prototype endsWith   function suffix            return this indexOf suffix  this length - suffix length      -1

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I just learned about this string library   http   stringjs com   Include the js file and then use the S variable like this   S  hi there   endsWith  hi there     It can also be used in NodeJS by installing it   npm install string   Then requiring it as the S variable   var S   require  string      The web page also has links to alternate string libraries  if this one doesn t take your fancy

User · Answer

A way to future proof and or prevent overwriting of existing prototype would be test check to see if it has already been added to the String prototype  Here s my take on the non-regex highly rated version    if  typeof String endsWith      function         String prototype endsWith   function  suffix            return this indexOf suffix  this length - suffix length      -1

User · Answer

if    mystring    substr -1 1             -- Or --  if    mystring    match

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if typeof String prototype endsWith      function                    String prototype endsWith        Check if given string locate at the end of current string         param  string  substring substring to locate in the current string          param  number   position end the endsWith check at that position         return  boolean                 edition ECMA-262 6th Edition  15 5 4 23             String prototype endsWith   function substring  position            substring   String substring            var subLen   substring length   0           if   subLen  return true   Empty string          var strLen   this length           if  position     void 0  position   strLen          else position   position   0           if  position  lt  1  return false           var fromIndex    strLen  lt  position   strLen   position  - subLen           return  fromIndex  gt   0    subLen     -fromIndex               amp  amp                    position     0                    if position not at the and of the string  we can optimise search substring                     by checking first symbol of substring exists in search position in current string                    this charCodeAt fromIndex      substring charCodeAt 0   fast false                            amp  amp  this indexOf substring  fromIndex      fromIndex                      Benefits    This version is not just re-using indexOf  Greatest performance on long strings  Here is a speed test http   jsperf com starts-ends-with 4 Fully compatible with ecmascript specification  It passes the tests

User · Answer

if    mystring    substr -1 1             -- Or --  if    mystring    match

User · Answer

This is the implementation of endsWith   String prototype endsWith   function  str      return  this length  gt   str length   amp  amp   this substr this length - str length      str

User · Answer

After all those long tally of answers  i found this piece of code simple and easy to understand   function end str  target      return str substr -target length     target

User · Answer

UPDATE  Nov 24th  2015   This answer is originally posted in the year 2010  SIX years back   so please take note of these insightful comments   Shauna -   Update for Googlers - Looks like ECMA6 adds this function  The MDN article also shows a polyfill  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects String endsWith   T J  Crowder -   Creating substrings isn t expensive on modern browsers  it may well have been in 2010 when this answer was posted  These days  the simple this substr -suffix length      suffix approach is fastest on Chrome  the same on IE11 as indexOf  and only 4  slower  fergetaboutit territory  on Firefox  jsperf com endswith-stackoverflow 14 And faster across the board when the result is false  jsperf com endswith-stackoverflow-when-false Of course  with ES6 adding endsWith  the point is moot   -    ORIGINAL ANSWER  I know this is a year old question    but I need this too and I need it to work cross-browser so    combining everyone s answer and comments and simplifying it a bit  String prototype endsWith   function suffix        return this indexOf suffix  this length - suffix length      -1       Doesn t create a substring Uses native indexOf function for fastest results Skip unnecessary comparisons using the second parameter of indexOf to skip ahead Works in Internet Explorer NO Regex complications   Also  if you don t like stuffing things in native data structure s prototypes  here s a standalone version  function endsWith str  suffix        return str indexOf suffix  str length - suffix length      -1      EDIT  As noted by  hamish in the comments  if you want to err on the safe side and check if an implementation has already been provided  you can just adds a typeof check like so  if  typeof String prototype endsWith      function         String prototype endsWith   function suffix            return this indexOf suffix  this length - suffix length      -1

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