javascript validation for textbox

[vivekgs2007]

im new to javascript, i want a javascript validation for validating txtbox

my requirement is to enter string in txtbox in dis form only(12_A-34)

i.e first 2 digit and 1 underscore and 1 Capital letter and 1 hypen and 2 digits.

if any thing change in the format it should alert msg,

it should enter only in this (12_A-34) format only

[Dormilich]

that looks like a job for a Regular Expression.

[vivekgs2007]

How to do that regular expression validation

[rahuljaiswal1987]

It'll be something like this:

<script language="JavaScript1.2">
function checkpostal(){
var re5digit=/^\d{5}$/ //regular expression defining a 5 digit number
if (document.myform.myinput.value.search(re5digit)==-1) //if match failed
alert("Please enter a valid 5 digit number inside form")
}
</script>
 
<form name="myform">
<input type="text" name="myinput" size=15>
<input type="button" onClick="checkpostal()" value="check">
 
</form>

Its a validation code for a 5 digit number. You just need to change the logic according to your need.



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