CODEWITHSUNDEEP
javascripthtmlregex
RahulOnRails
RahulOnRails

Reputation: 6542

Regular Expression for Alphabets + Numeric Value

I am working on a Java-script, for which I need regular expression to check whether the entered text in text-box should be combination of alphabets and numeric value.

I tried NaN function of java-script but string should be of minimum-size & maximum-size of length 4 and start with Alphabet as first element and remaining 3 element should be numbers.

For example : Regular expression for A123, D456, a564 and not for ( AS23, 1234, HJI1 )

Please suggest me !!!

Code Here:

<script type="text/javascript">
  var textcode = document.form1.code.value;
  function fourdigitcheck(){
    var textcode = document.form1.code.value;
    alert("textcode:"+textcode);
    var vmatch = /^[a-zA-Z]\d{3}$/.test("textcode");
    alert("match:"+vmatch);
    }
</script>
<form name="form1">
 Enter your Number  <input type="text" name="code" id="code"   onblur="fourdigitcheck()" />
</form>

Upvotes: 1

Views: 10086

Answers (6)

rubber boots
rubber boots

Reputation: 15204

Minimal example:

<html>
<head>
</head>
<body>
<form id="form" name="form" action="#">
  <input type="text" onkeyup=
   "document.getElementById('s').innerHTML=this.value.match(/^[a-z]\d\d\d$/i)?'Good':'Fail'" 
   />
  <span id="s">?</span>
</form>
</html>

Upvotes: 0

Alex
Alex

Reputation: 933

If you want both upper and lower case letters then /^[A-Za-z][0-9]{3}$/

else if letters are upper case then /^[A-Z][0-9]{3}$/

Upvotes: 1

MartyIX
MartyIX

Reputation: 28676

Regexp:

var match = /^[a-zA-Z][0-9]{3}$/.test("A456"); // match is true
var match = /^[a-zA-Z][0-9]{3}$/.test("AB456"); // match is false

http://www.regular-expressions.info/javascriptexample.html - there's an online testing tool where you can check if it works all right.

Upvotes: 3

Floyd
Floyd

Reputation: 1918

^[A-Z]{1}\d{3}$

or shorter

^[A-Z]\d{3}$

Description:

// ^[A-Z]\d{3}$
// 
// Assert position at the start of the string or after a line break character «^»
// Match a single character in the range between "A" and "Z" «[A-Z]»
// Match a single digit 0..9 «\d{3}»
//    Exactly 3 times «{3}»
// Assert position at the end of the string or before a line break character «$»

Test:

/*
A123 -> true
D456 -> true
AS23 -> false
1234 -> false
HJI1 -> false
AB456 -> false
*/

Upvotes: 4

alxx
alxx

Reputation: 9897

/[A-Z][0-9]{3}/

Upvotes: 1

Skilldrick
Skilldrick

Reputation: 70879

This website will tell you exactly what you need to know.

Upvotes: 3

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