javascript - Allow only numbers to be typed in a textbox

Question

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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.