Validating Forms in Javascript

Question

From a question in this site I found the following code of romaintaz:

<script type="text/javascript">
function testField(field) {
    var regExpr = new RegExp("^\d*\.?\d*$");
    if (!regExpr.test(field.value)) {
      // Case of error
      field.value = "";
    }
}

</script>

My question now is: How can I make this validator only accept numbers and nothing else? Any integer.

Christian C. Salvadó · Accepted Answer · 2009-11-26 00:40:11Z

2

You can chance your regular expression to accept only numeric digits (only integer numbers):

function testField(field) {
    var regExpr = /^[0-9]+$/;
    if (!regExpr.test(field.value)) {
      // Case of error
      field.value = "";
    }
}

answered Nov 26, 2009 at 0:40

Christian C. Salvadó

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1 Comment

Christian C. Salvadó Over a year ago

You're welcome @dohkoxar, BTW if you need to check negative integers, just add an optional - character to the RegExp: /^-?[0-9]+$/

Dmytrii Nagirniak · Accepted Answer · 2009-11-26 00:43:55Z

0

This will accept positive and negative integer number with not more than 17 digits.

<script type="text/javascript">
function testField(field) {
    var regExpr = new RegExp("^-?\d{1,17}$");
    if (!regExpr.test(field.value)) {
      // Case of error
      field.value = "";
    }
}

</script>

answered Nov 26, 2009 at 0:43

Dmytrii Nagirniak

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Comments

mmorrisson · Accepted Answer · 2009-11-26 00:47:39Z

0

To allow the possibly of signed integers:

function testField(field) {
    var regExpr = new RegExp("^(\+|-)?\d+$");
    if (!regExpr.test(field.value)) {
      // Not a number
      field.value = "";
    }
}

answered Nov 26, 2009 at 0:47

mmorrisson

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