How do I check if string contains substring

Question

I have a shopping cart that displays product options in a dropdown menu and if they select  yes   I want to make some other fields on the page visible    The problem is that the shopping cart also includes the price modifier in the text  which can be different for each product  The following code works     document  ready function            select id  Engraving     change function             var str      select id  Engraving   option selected   text            if  str     Yes     6 95                      engraving   show              else                   engraving   hide                            However I would rather use something like this  which doesn t work     document  ready function            select id  Engraving     change function             var str      select id  Engraving   option selected   text            if  str     Yes                     engraving   show              else                   engraving   hide                            I only want to perform the action if the selected option contains the word  Yes   and would ignore the price modifier

User · Answer

You can also check if the exact word is contained in a string. E.g.:

function containsWord(haystack, needle) {
    return (" " + haystack + " ").indexOf(" " + needle + " ") !== -1;
}

Usage:

containsWord("red green blue", "red"); // true
containsWord("red green blue", "green"); // true
containsWord("red green blue", "blue"); // true
containsWord("red green blue", "yellow"); // false

This is how jQuery does its hasClass method.

User · Answer

It s pretty late to write this answer  but I thought of including it anyhow  String prototype now has a method includes which can check for substring  This method is case sensitive   var str    It was a good date   console log str includes  good        shows true console log str includes  Good        shows false   To check for a substring  the following approach can be taken   if  mainString toLowerCase   includes substringToCheck toLowerCase              mainString contains substringToCheck     Check out the documentation to know more

User · Answer

You could use search or match for this   str search   Yes     will return the position of the match  or -1 if it isn t found

User · Answer

Like this   if  str indexOf  Yes    gt   0       or you can use the tilde operator   if   str indexOf  Yes      This works because indexOf   returns -1 if the string wasn t found at all   Note that this is case-sensitive  If you want a case-insensitive search  you can write   if  str toLowerCase   indexOf  yes    gt   0    Or   if   yes i test str

User · Answer

None of the above worked for me as there were blank spaces  but this is what I did  tr   table getElementsByTagName  tr         for  i   0  i  lt  tr length  i              td   tr i  getElementsByTagName  td   0           bottab style display  none           bottab2 style display  none           if  td            var getvar td outerText replace   s                       if  getvar  filter                   tr i  style display                    else                  tr i  style display    none

User · Answer

you can define an extension method and use it later   String prototype contains   function it         return this indexOf it     -1        so that you can use in your page anywhere like   var str  hello how are you   str contains  are      which returns true   Refer below post for more extension helper methods  Javascript helper methods

User · Answer

If you are capable of using libraries  you may find that Lo-Dash JS library is quite useful  In this case  go ahead and check   contains    replaced by   includes   as of v4     Note Lo-Dash convention is naming the library object    Don t forget to check installation in the same page to set it up for your project      contains  foo    oo             true   contains  foo    bar            false    Equivalent with     foo   contains  oo             true    foo   contains  bar            false   In your case  go ahead and use     contains str   Yes       or    str  contains  Yes        whichever one you like better

User · Answer

The includes   method determines whether one string may be found within another string  returning true or false as appropriate  Syntax  -string includes searchString   position   searchString -A string to be searched for within this string  position -Optional  The position in this string at which to begin searching for searchString  defaults to 0   string    LOL   console log string includes  lol        returns false  console log string includes  LOL        returns true

User · Answer

You can use this Polyfill in ie and chrome  if     contains  in String prototype         String prototype contains   function  str  startIndex             use strict           return -1     String prototype indexOf call this  str  startIndex

User · Answer

Another way   var testStr    This is a test    if testStr contains  test         alert  String Found           Tested on Firefox  Safari 6 and Chrome 36

User · Answer

I know that best way is str indexOf s      -1  http   hayageek com javascript-string-contains   I suggest another way str replace s1          str     x000D   x000D  var str    Hello World    s1    ello   s2    elloo   x000D  alert str replace s1          str   x000D  alert str replace s2          str   x000D   x000D   x000D

User · Answer

Returns number of times the keyword is included in the string   var count    I have one keyword  match  keyword g   var clean count    count   false   count length

User · Answer

ECMAScript 6 introduces String prototype includes  previously named contains   It can be used like this    foobar  includes  foo       true  foobar  includes  baz       false   It also accepts an optional second argument which specifies the position at which to begin searching    foobar  includes  foo   1      false  foobar  includes  bar   1      true   It can be polyfilled to make it work on old browsers

[javascript] How do I check if string contains substring?

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