Best way to restrict a text field to numbers only?

user_453465 0
Viewed 165656

I'm using the following Javascript to restrict a text field on my website to only accept numerical input, and no other letters or characters. The problem is, it REALLY rejects all other key inputs, like ctrl-A to select the text, or even any other browser functions like ctrl-T or ctrl-W while the text box is selected. Does anyone know of a better script to only allow numerical input, but not block normal commands (that aren't being directly input into the field)? Thanks Here is the code I'm using now:

function numbersonly(e, decimal) 
{
    var key;
    var keychar;

    if (window.event) 
        key = window.event.keyCode;
    else if (e) 
        key = e.which;
    else 
        return true;

    keychar = String.fromCharCode(key);

    if ((key==null) || (key==0) || (key==8) ||  (key==9) || (key==13) || (key==27))
       return true;     
    else if ((("0123456789").indexOf(keychar) > -1))
       return true;
    else if (decimal && (keychar == "."))
       return true;        
    else
       return false;
}

Edit: None of the solutions provided have solved my problem of allowing commands like ctrl-A while the text box is selected. That was the whole point of my asking here, so I have gone back to using my original script. Oh well.

textfield numbers textbox html javascript
29 Answers

Add <script type="text/javascript" src="jquery.numeric.js"></script> then use

 $("element").numeric({ decimal: false, negative: false });
user_19116190

All of the answers are outdated, lengthy and will cause annoyance to your users. Most of them don’t even filter or allow pasted content.

Instead of filtering the input, do some validation before submitting the form and then also server-side.

HTML has validation included:

<input type="number" pattern="[0-9]+">

This also enables the number keyboard on mobile.

user_2889060 
  document.getElementById('myinput').onkeydown = function(e) {
      if(!((e.keyCode > 95 && e.keyCode < 106)
      || (e.keyCode > 47 && e.keyCode < 58) 
      || e.keyCode == 8
      || e.keyCode == 9)) {
        return false;
      }
  }
user_31215180

This JavaScript function will be used to restrict alphabets and special characters in Textbox , only numbers, delete, arrow keys and backspace will be allowed. JavaScript Code Snippet - Allow Numbers in TextBox, Restrict Alphabets and Special Characters

Tested in IE & Chrome.

JavaScript function

<script type="text/javascript">
    /*code: 48-57 Numbers
      8  - Backspace,
      35 - home key, 36 - End key
      37-40: Arrow keys, 46 - Delete key*/
    function restrictAlphabets(e){
        var flag = false;
var x = e.which || e.keycode;
if ((x >= 48 && x <= 57) || x == 8 ||
    (x >= 35 && x <= 40) || x == 46)
    flag = true;
else
    flag = false;

if (flag && e.keyCode === 46 && $(e.currentTarget).val().split('.').length === 2) {
    flag = false;
}

return flag;
    }
</script>

HTML Source Code with JavaScript

<html>
    <head>
        <title>JavaScript - Allow only numbers in TextBox (Restrict Alphabets and Special Characters).</title>
        <script type="text/javascript">
            /*code: 48-57 Numbers
              8  - Backspace,
              35 - home key, 36 - End key
              37-40: Arrow keys, 46 - Delete key*/
            function restrictAlphabets(e){
                var x=e.which||e.keycode;
                if((x>=48 && x<=57) || x==8 ||
                    (x>=35 && x<=40)|| x==46)
                    return true;
                else
                    return false;
            }
        </script>
    </head>
<body style="text-align: center;">
    <h1>JavaScript - Allow only numbers in TextBox (Restrict Alphabets and Special Characters).</h1>
    <big>Enter numbers only: </big>
    <input type="text" onkeypress='return restrictAlphabets(event)'/>
</body>

</html>

Refrence

user_50305790

I am using below in Angular to restrict character

in HTML

For Number Only

<input
 type="text"
 id="score"
 (keypress) ="onInputChange($event,'[0-9]')"
 maxlength="3"
 class="form-control">

for Alphabets Only

<input
     type="text"
     id="state"
     (keypress) ="onInputChange($event,'[a-zA-Z]')"
     maxlength="3"
     class="form-control">

In TypeScript

 onInputChange(event: any, inpPattern:string): void {   
        var input = event.key; 
        if(input.match(inpPattern)==null){
         event.preventDefault();
        }
      }
user_4518940
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