Validate format of an email address - no regex, no plugins jquery

Question

I've got a function which almost works - it validates an email address format in the following form:

Must have an @ symbol
Must have some string after @ symbol.
Must have a '.' followed by another string after that.

It doesn't work at the moment because I don't know how to correctly insert a variable that accepts any string that the user inputs - how can this be achieved?

"how can this be achieved" with regex. But seriously, why no regex? — Petah, Feb 03 '13 at 23:24
The `regex` built into the jQuery Validate plugin already handles this very well. Too bad you don't want to use it. — Sparky, Feb 04 '13 at 16:49

score 2 · Accepted Answer · answered Feb 04 '13 at 00:08

I am not going to profess to being an email validation expert.

If you really must not use regex, could do something along the lines of:

function validateEmail(str){
   var index_at= str.indexOf('@')
   if( index_at === -1){
       return false;
   }   

    var name= str.substr(0,index_at);
     /* should test name for other invalids*/

    var domain=str.substr(index_at+1);
    /* should check for extra "@" and any other checks that would invalidate an address of which there are likely many*/
    if( domain.indexOf('@') !=-1){
        return false;
    }
    /* dot can't be first character of domain*/
   return domain.indexOf('.') >0;

}

DEMO: http://jsfiddle.net/v43Hw/

Strongly recommend using a regex that has been tested against email standards for greater reliability.

Validate format of an email address - no regex, no plugins jquery

1 Answers1