I need to make sure that a certain <input> field only takes numbers as value.
The input is not part of a form. Hence it doesn't get submitted, so validating during submission is not an option. I want the user to be unable to type in any characters other than numbers.
Is there a neat way to achieve this?
You can use HTML5 input type number to restrict only number entries:
<input type="number" name="someid" />
This will work only in HTML5 complaint browser. Make sure your html document's doctype is:
<!DOCTYPE html>
See also https://github.com/jonstipe/number-polyfill for transparent support in older browsers.
Update: There is a new and very simple solution for this:
It allows you to use any kind of input filter on a text
<input>, including various numeric filters. This will correctly handle Copy+Paste, Drag+Drop, keyboard shortcuts, context menu operations, non-typeable keys, and all keyboard layouts.
See this answer or try it yourself on JSFiddle.
For general purposes, you can have JS validation as below:
function isNumberKey(evt) {
var charCode = (evt.which) ? evt.which : evt.keyCode
if (charCode > 31 && (charCode < 48 || charCode > 57))
return false;
return true;
}<input name="someid" type="number" onkeypress="return isNumberKey(event)" />If you want to allow decimals replace the if-conditio" with this:
if (charCode > 31 && (charCode != 46 &&(charCode < 48 || charCode > 57)))