javascript - URL regex validation

Question

i made that:

 /^(http[s]?://){0,1}(www.){0,1}[a-zA-Z0-9.-]+.[a-zA-Z]{2,5}[.]{0,1}

and checked it with a validator but on my page it is not working:

var re = /^(http[s]?://){0,1}(www.){0,1}[a-zA-Z0-9.-]+.[a-zA-Z]{2,5}[.]{0,1};
if (!re.test(url)) { 
    alert("url error");
    return false;
}

i get this error

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)
Timestamp: Tue, 30 Nov 2010 14:23:10 UTC


Message: Expected ')' in regular expression
Line: 781
Char: 23
Code: 0
URI: http://*************************

Answer 1

You have to escape your special characters (/ and that . after www in this case) and att the missing trailing /, like this:

var re = /^(http[s]?://){0,1}(www.){0,1}[a-zA-Z0-9.-]+.[a-zA-Z]{2,5}[.]{0,1}/;
if (!re.test(url)) { 
    alert("url error");
    return false;
}