Check whether an input string contains a number in javascript

Question

My end goal is to validate an input field  The input may be either alphabetic or numeric

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This is what you need        var hasNumber     d            hasNumber test  quot ABC33SDF quot       true       hasNumber test  quot ABCSDF quot       false

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You can do this using javascript  No need for Jquery or Regex  function isNumeric n      return  isNaN parseFloat n    amp  amp  isFinite n       While implementing  var val      yourinputelement   val    if isNumeric val     alert  number       else   alert  not number        Update  To check if a string has numbers in them  you can use regular expressions to do that  var matches   val match   d  g   if  matches    null        alert  number

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One way to check it is to loop through the string and return true  or false depending on what you want  when you hit a number   function checkStringForNumbers input       let str   String input       for  let i   0  i  lt  str length  i                   console log str charAt i            if  isNaN str charAt i                 if the string is a number  do the following             return true

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If I m not mistaken  the question requires  contains number   not  is number   So   function hasNumber myString      return   d  test myString

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You can also try lodash   const isNumeric   number   gt       isFinite   parseInt number    amp  amp     isNaN   parseInt number

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It s not bulletproof by any means  but it worked for my purposes and maybe it will help someone   var value      input   val     if parseInt value       console log value   is a number         else     console log value   is NaN

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Using Regular Expressions with JavaScript  A regular expression is a special text string for describing a search pattern  which is written in the form of  pattern modifiers where  pattern  is the regular expression itself  and  modifiers  are a series of characters indicating various options    nbsp  nbsp  nbsp  nbsp  nbsp  nbsp  nbsp  nbsp  nbsp The character class is the most basic regex concept after a literal match  It makes one small sequence of characters match a larger set of characters  For example   A-Z  could stand for the upper case alphabet  and  d could mean any digit   From below example   contains alphaNumeric    It checks for string contains either letter or number  or  both letter and number  The hyphen  -  is ignored  onlyMixOfAlphaNumeric    It checks for string contain both letters and numbers only of any sequence order    Example     function matchExpression  str         var rgularExp             contains alphaNumeric        -      -  A-Za-z0-9-     lt  -             containsNumber     d            containsAlphabet     a-zA-Z             onlyLetters      A-Za-z              onlyNumbers      0-9              onlyMixOfAlphaNumeric       0-9   a-zA-Z    a-zA-Z   0-9    0-9a-zA-Z                var expMatch           expMatch containsNumber   rgularExp containsNumber test str       expMatch containsAlphabet   rgularExp containsAlphabet test str       expMatch alphaNumeric   rgularExp contains alphaNumeric test str        expMatch onlyNumbers   rgularExp onlyNumbers test str       expMatch onlyLetters   rgularExp onlyLetters test str       expMatch mixOfAlphaNumeric   rgularExp onlyMixOfAlphaNumeric test str        return expMatch        HTML Element attribute s id  name  with dynamic values  var id1    Yash   id2  777   id3   Yash777   id4   Yash777Image4      id11   image5 64   id22   55-5 6   id33   image Yash   id44   image-Yash      id12    -    console log   Only Letters  n    matchExpression id1     console log   Only Numbers  n    matchExpression id2     console log   Only Mix of Letters and Numbers  n    matchExpression id3     console log   Only Mix of Letters and Numbers  n    matchExpression id4      console log   Mixed with Special symbols     console log   Letters and Numbers   n    matchExpression id11     console log   Numbers  -   n    matchExpression id22     console log   Letters   n    matchExpression id33     console log   Letters  -   n    matchExpression id44      console log   Only Special symbols   n    matchExpression id12         Out put    Only Letters     containsNumber  false  containsAlphabet  true  alphaNumeric  true  onlyNumbers  false  onlyLetters  true   mixOfAlphaNumeric  false  Only Numbers     containsNumber  true  containsAlphabet  false  alphaNumeric  true  onlyNumbers  true  onlyLetters  false   mixOfAlphaNumeric  false  Only Mix of Letters and Numbers     containsNumber  true  containsAlphabet  true  alphaNumeric  true  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  true  Only Mix of Letters and Numbers     containsNumber  true  containsAlphabet  true  alphaNumeric  true  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  true  Mixed with Special symbols Letters and Numbers      containsNumber  true  containsAlphabet  true  alphaNumeric  false  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  false  Numbers  -      containsNumber  true  containsAlphabet  false  alphaNumeric  false  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  false  Letters      containsNumber  false  containsAlphabet  true  alphaNumeric  false  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  false  Letters  -      containsNumber  false  containsAlphabet  true  alphaNumeric  true  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  false  Only Special symbols      containsNumber  false  containsAlphabet  false  alphaNumeric  false  onlyNumbers  false  onlyLetters  false   mixOfAlphaNumeric  false    java Pattern Matching with Regular Expressions

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This code also helps in   To Detect Numbers in Given String  when numbers found it stops its execution   function hasDigitFind  str       this  code    10     When empty string found     var  strArray          if   str             str      undefined     str      null         strArray    str  split          for var i   0  i  lt   strArray length  i            if  isNaN parseInt  strArray i               this  code    -1          break          else           this  code    1                       return this  code

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We can check it by using     a-zA-Z   test e  Just run snippet and check   x000D   x000D  function handleValueChange       if      a-zA-Z   test document getElementById  textbox id   value           var x   document getElementById  result          x innerHTML    String does not contain number       else       var x   document getElementById  result        x innerHTML    String does contains number         x000D  input     padding  5px    x000D   lt input type  text  id  textbox id  placeholder  Enter string here     oninput  handleValueChange    gt   lt p id  result  gt  lt  p gt  x000D   x000D   x000D

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Below code checks for same number  sequence number and reverse number sequence  function checkNumSequnce arrayNM2        inseqCounter 1      continousSeq   1      decsequenceConter   1      var isequence   true      for  i 0 i lt arrayNM2 length-1 i            j i 1        if  arrayNM2 i     arrayNM2 i 1                      if inseqCounter  gt  1    decsequenceConter  gt  1                       isequence    false  break                                             continousSeq                                                               else if  arrayNM2 j - arrayNM2 i     1                if decsequenceConter  gt  1    continousSeq  gt  1                   isequence    false  break                                       inseqCounter                                                      else if arrayNM2 i - arrayNM2 j     1                 if inseqCounter  gt  1    continousSeq  gt  1                      isequence    false  break                                 decsequenceConter             else                isequence  false                break                    console log  quot isequence   quot   isequence

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To test if any char is a number  without overkill   to be adapted as need   x000D   x000D  const s    EMA618   function hasInt me     let i   1 a   me split     b      c         a forEach function e      if   isNaN e         console log  CONTAIN NUMBER     e    AT POSITION   a indexOf e     gt  TOTAL COUNT   i         c    e      i        else  b    e         console log  STRING IS     b     NUMBER IS     c        if  i     0       return false        return b     else       return true        return  c         hasInt s  x000D   x000D   x000D

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function validate            var re      A-Za-z          if re test document getElementById  textboxID   value          alert  Valid Name         else        alert  Invalid Name

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parseInt provides integers when the string begins with the representation of an integer    parseInt  1a    is  1     so perhaps   isInteger    s - gt    s is  parseInt s  toString    and  s isnt  NaN    isInteger  a   is false  isInteger  1a   is false  isInteger  NaN   is false  isInteger  -42   is true   Pardon my CoffeeScript

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You can do this using javascript  No need for Jquery or Regex function isNumeric n       return  isNaN n

[javascript] Check whether an input string contains a number in javascript

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