RegEx for Javascript to allow only alphanumeric

user_48655 0
Viewed 545412

I need to find a reg ex that only allows alphanumeric. So far, everyone I try only works if the string is alphanumeric, meaning contains both a letter and a number. I just want one what would allow either and not require both.

javascript regex
21 Answers
/^[a-z0-9]+$/i

^         Start of string
[a-z0-9]  a or b or c or ... z or 0 or 1 or ... 9
+         one or more times (change to * to allow empty string)
$         end of string    
/i        case-insensitive

Update (supporting universal characters)

if you need to this regexp supports universal character you can find list of unicode characters here.

for example: /^([a-zA-Z0-9\u0600-\u06FF\u0660-\u0669\u06F0-\u06F9 _.-]+)$/

this will support persian.

user_241810

Use the word character class. The following is equivalent to a ^[a-zA-Z0-9_]+$:

^\w+$

Explanation:

  • ^ start of string
  • \w any word character (A-Z, a-z, 0-9, _).
  • $ end of string

Use /[^\w]|_/g if you don't want to match the underscore.

Chase_Seibert_76790 
^\s*([0-9a-zA-Z]*)\s*$

or, if you want a minimum of one character:

^\s*([0-9a-zA-Z]+)\s*$

Square brackets indicate a set of characters. ^ is start of input. $ is end of input (or newline, depending on your options). \s is whitespace.

The whitespace before and after is optional.

The parentheses are the grouping operator to allow you to extract the information you want.

EDIT: removed my erroneous use of the \w character set.

cletus_183930

For multi-language support:

var filtered = 'Hello Привет 你好 123_456'.match(/[\p{L}\p{N}\s]/gu).join('')
console.log(filtered) // --> "Hello Привет 你好 123456"

This matches any letter, number, or space in most languages.

  • [...] -> Match with conditions
  • [ab] -> Match 'a' OR 'b'
  • \p{L} -> Match any letter in any language
  • \p{N} -> Match any number in any language
  • \s -> Match a space
  • /g -> Don't stop after first match
  • /u -> Support unicode pattern matching

Ref: https://javascript.info/regexp-unicode

user_12027570

I have string similar to Samsung Galaxy A10s 6.2-Inch (2GB,32GB ROM) Android 9.0, (13MP+2MP)+ 8MP Dual SIM 4000mAh 4G LTE Smartphone - Black (BF19)

Below is what i did:

string.replace(/[^a-zA-Z0-9 ,._-]/g, '').split(',').join('-').split(' ').join('-').toLowerCase()

Notice i allowed ,._- then use split() and join() to replace , to - and space to - respectively.

I ended up getting something like this: samsung-galaxy-a10s-6.2-inch-2gb-32gb-rom-android-9.0-13mp-2mp-8mp-dual-sim-4000mah-4g-lte-smartphone-black-bf19-20 which is what i wanted.

There might be a better solution but this is what i found working fine for me.

user_48993150

Input these code to your SCRATCHPAD and see the action.

var str=String("Blah-Blah1_2,oo0.01&zz%kick").replace(/[^\w-]/ig, '');
user_27633300

JAVASCRIPT to accept only NUMBERS, ALPHABETS and SPECIAL CHARECTERS

document.getElementById("onlynumbers").onkeypress = function (e) {
 onlyNumbers(e.key, e)
};

document.getElementById("onlyalpha").onkeypress = function (e) {
 onlyAlpha(e.key, e)
};

document.getElementById("speclchar").onkeypress = function (e) {
 speclChar(e.key, e)
};

function onlyNumbers(key, e) {
 var letters = /^[0-9]/g; //g means global
 if (!(key).match(letters)) e.preventDefault();
}

function onlyAlpha(key, e) {
 var letters = /^[a-z]/gi; //i means ignorecase
 if (!(key).match(letters)) e.preventDefault();
}

function speclChar(key, e) {
 var letters = /^[0-9a-z]/gi;
 if ((key).match(letters)) e.preventDefault();
}
<html>
   <head></head>
   <body>
      Enter Only Numbers: 
      <input id="onlynumbers" type="text">
      <br><br>
      Enter Only Alphabets: 
      <input id="onlyalpha" type="text" >
      <br><br>
      Enter other than Alphabets and numbers like special characters: 
      <input id="speclchar" type="text" >
   </body>
</html>

user_88919310

A little bit late, but this worked for me:

/[^a-z A-Z 0-9]+/g

a-z : anything from a to z.

A-Z : anything from A to Z (upper case).

0-9 : any number from 0 to 9.

It will allow anything inside square brackets, so let's say you want to allow any other character, for example, "/" and "#", the regex would be something like this:

/[^a-z A-Z 0-9 / #]+/g

This site will help you to test your regex before coding. https://regex101.com/

Feel free to modify and add anything you want into the brackets. Regards :)

user_104491060

Try this... Replace you field ID with #name... a-z(a to z), A-Z(A to Z), 0-9(0 to 9)

jQuery(document).ready(function($){
    $('#name').keypress(function (e) {
        var regex = new RegExp("^[a-zA-Z0-9\s]+$");
        var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);
        if (regex.test(str)) {
            return true;
        }
        e.preventDefault();
        return false;
    });
});
user_39923750

Save this constant

const letters = /^[a-zA-Z0-9]+$/

now, for checking part use .match()

const string = 'Hey there...' // get string from a keyup listner
let id = ''
// iterate through each letters
for (var i = 0; i < string.length; i++) {
  if (string[i].match(letters) ) {
    id += string[i]
  } else {
    // In case you want to replace with something else
    id += '-'  
  }
}
return id
user_106735280

Alphanumeric with case sensitive:

if (/^[a-zA-Z0-9]+$/.test("SoS007")) {
  alert("match")
}
user_16611860

Only accept numbers and letters (No Space)

function onlyAlphanumeric(str){
  str.value=str.value.replace(/\s/g, "");//No Space
  str.value=str.value.replace(/[^a-zA-Z0-9 ]/g, "");
}
<div>Only accept numbers and letters </div>
<input type="text"  onKeyUp="onlyAlphanumeric(this);" >

user_62494830

Jquery to accept only NUMBERS, ALPHABETS and SPECIAL CHARECTERS 

<html>
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
</head>

<body>
Enter Only Numbers: 
<input type="text" id="onlynumbers">
<br><br>
Enter Only Alphabets: 
<input type="text" id="onlyalpha">
<br><br>
Enter other than Alphabets and numbers like special characters: 
<input type="text" id="speclchar">

<script>
    $('#onlynumbers').keypress(function(e) {
      var letters=/^[0-9]/g; //g means global
      if(!(e.key).match(letters)) e.preventDefault();
 });
    
    $('#onlyalpha').keypress(function(e) {
      var letters=/^[a-z]/gi; //i means ignorecase
      if(!(e.key).match(letters)) e.preventDefault();
 });
    
    $('#speclchar').keypress(function(e) {
      var letters=/^[0-9a-z]/gi; 
      if((e.key).match(letters)) e.preventDefault();
 });
    </script>
</body>
</html>

**JQUERY to accept only NUMBERS , ALPHABETS and SPECIAL CHARACTERS **


<!DOCTYPE html>
    $('#onlynumbers').keypress(function(e) {
      var letters=/^[0-9]/g; //g means global
      if(!(e.key).match(letters)) e.preventDefault();
    });

    $('#onlyalpha').keypress(function(e) {
      var letters=/^[a-z]/gi; //i means ignorecase
      if(!(e.key).match(letters)) e.preventDefault();
    });

    $('#speclchar').keypress(function(e) {
      var letters=/^[0-9a-z]/gi; 
      if((e.key).match(letters)) e.preventDefault();
    });

<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js">

Enter Only Numbers:

Enter Only Alphabets:

Enter other than Alphabets and numbers like special characters: 

</body>
</html>
user_88919310

Also if you were looking for just Alphabetical characters, you can use the following regular expression:

/[^a-zA-Z]/gi

Sample code in typescript:

let samplestring = "!#!&34!# Alphabet !!535!!! is safe"

let regex = new RegExp(/[^a-zA-Z]/gi);
    let res = samplestring.replace(regex,'');

    console.log(res);

Note: if you are curious about RegEx syntax, visit regexr and either use the cheat-sheet or play with regular expressions.

Edit: alphanumeric --> alphabetical

user_85357030
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