Allow only numbers and special character(-) to be typed in a textbox

Question

I need to Allow only numbers and special character minus "-" to be typed in a textbox, plz help me i already have a number restriction, but wanna minus sign too.

thanks in advance

<script>
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;
}
</script>


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

You should have a look at the HTML5 [`pattern`](https://developer.mozilla.org/en/docs/Web/HTML/Element/input#attr-pattern) attribute. — Siguza, Jun 03 '17 at 20:33
pattern has browser support issue in IE old versions and not support in opera — jai, Jun 03 '17 at 20:35
Looks like you just copy + paste a code you did not understand. You just need to add another && charCode !==45 and it will work. — Jonas Wilms, Jun 03 '17 at 20:44
right Jonas it helps me and I already solved it, and thanks for your harsh words too — jai, Jun 03 '17 at 20:47
@jai im glad to hear that youve solved it. However, i did not want to be harsh in any way, im sorry for that — Jonas Wilms, Jun 03 '17 at 21:36

peterulb · Answer 1 · 2017-06-03T21:01:38.583

0

This regex will check for numbers and '-'. If there are other characters, they'll be replaced.

$('.input').keyup(function () {
    if (!this.value.match(/^(\d|-)+$/)) {
        this.value = this.value.replace(/[^0-9-]/g, '');
    }
});

No jQuery version:

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

function isNumber() {
    var inputField = document.getElementById('extra7');
    if (!inputField.value.match(/^(\d|-)+$/)) {
        inputField.value = inputField.value.replace(/[^0-9-]/g, '');
    }
}

edited Jun 03 '17 at 21:01

answered Jun 03 '17 at 20:50

peterulb

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if no `jquery` is tagged Q&A is supposed to be in plain JS. – Nikhil Vartak Jun 03 '17 at 20:52
@niksofteng right, added it – peterulb Jun 03 '17 at 21:02

score 0 · Accepted Answer · answered Jun 03 '17 at 20:55

Adding !=45 is not sufficient. You need to prevent the acceptance of invalid key inputs too. Returning true/false will still allow user to type those keys and your code then will seem to do nothing.

if ((charCode < 48 || charCode > 57) && charCode != 45) {
   evt.preventDefault();
}

This way only valid key inputs will appear in text box.

Allow only numbers and special character(-) to be typed in a textbox

2 Answers2