JavaScript电子邮件正则表达式匹配

Question

Please see the Javascript code below. The else if block which is doing a check for email pattern is not allowing any of the email ids . What does the match() function return? Please help.

Used test()

empty field :working fine wron mail id : working fine Correct email id : not working

var pattern = new RegExp("/^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/");
   if(!accountantEmail){
       $("#infoTextMsg").hide();
       $("#accountantEmailNoDataErr").show();
       $("#accountantEmailInvalidFormat").hide();
       $("#accountant_email").focus();
       return false;
   }
   else if(!(pattern.test(accountantEmail))){
       $("#accountantEmailInvalidFormat").show();
       $("#infoTextMsg").hide();
       $("#accountantEmailNoDataErr").hide();
       $("#accountant_email").focus();
       return false;
   }

Answer 1

Using regular expressions is probably the best way. Here's an example ( live demo ):

function validateEmail(email) 
{ 
    var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
        return re.test(email);
} 

But keep in mind that one should not rely only upon JavaScript validation. JavaScript can easily be disabled. This should be validated on the server side as well.

Answer 2

Javascript match returns an array containing the matches.

Here's the regular expression I use:

var pattern = "[-0-9a-zA-Z.+_]+@[-0-9a-zA-Z.+_]+\.[a-zA-Z]{2,4}";

if(!(accountantEmail.match(pattern))) {
    return false;
}

Answer 3

For validation scenarios, you should use the RegExp#test function.

var pattern = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;

if (!pattern.test(accountantEmail)) {
    $("#accountantEmailInvalidFormat").show();
    $("#infoTextMsg").hide();
    $("#accountantEmailNoDataErr").hide();
    $("#accountant_email").focus();
    return false;
}

As commented on the other posts, the match function is intended for group capturing.

Also note that you were specifying your pattern with an / on it's beginning. This isn't necessary if you're specifying a RegExp as a string.