Allow only numbers to be typed in a textbox [duplicate]

Question

How to allow only numbers to be written in this textbox ?

<input type="text" class="textfield" value="" id="extra7" name="extra7"> 

Answer 1

You could subscribe for the onkeypress event:

<input type="text" class="textfield" value="" id="extra7" name="extra7" onkeypress="return isNumber(event)" /> 

and then define the isNumber function:

function isNumber(evt) {     evt = (evt) ? evt : window.event;     var charCode = (evt.which) ? evt.which : evt.keyCode;     if (charCode > 31 && (charCode < 48 || charCode > 57)) {         return false;     }     return true; } 

You can see it in action here.

Answer 2

With HTML5 you can do

<input type="number"> 

You can also use a regex pattern to limit the input text.

<input type="text" pattern="^[0-9]*$" />