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Another Form Validation Question…

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Mar 31.2003

How would I go about validating this field so that it only accept exactly 12 numbers

if (document.form.idnum.value==””) {
window.alert (“Please enter your ID Number!”);
document.form.idnum.focus();
return false;
}

if (isNaN(document.form.idnum.value)) {
window.alert (“Your ID Number Must be Numerical and contain 12 Digits!”);
document.form.idnum.focus();
return false;
}

hte form validates ok at present for a null value and a numerical value but i would like it to validate for 12 only as well… TIA

to post a comment
JavaScript

3 Comments(s) ↴

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@khalidali63Mar 31.2003 — you can use an html elements attribute.

input tag has an attribute "maxlength"

you can set it in the text fields html declaration.

For e.g in this case

<input type="text" name ="idnum" maxlength="12"> will take care of that you won't need javascript to validate that.

Cheers

Khalid
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@ozzauthorMar 31.2003 — But what happens if someone only types in 10 numbers? The idnum must be exactly 12.
Copy linkTweet thisAlerts:
@khalidali63Mar 31.2003 — in that case you can add to this line

if (isNaN(document.form.idnum.value)) {

as

if (isNaN(document.form.idnum.value) && document.form.idnum.value.length<12

and so on
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