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Non-RegExp Email Validation Script by BillyRayPreachersSon
Posted: 21 Feb 05 (Edited 27 Jun 07)

If you are looking for an email validation script that doesn't require RegExp (and would therefore be easier to understand if you don't know RegExp very well, like myself), consider something like this:


function validateEmailAddress(emailToValidate) {
    if (emailToValidate == '' || typeof(emailToValidate) == 'undefined') return(false);
    emailToValidate = stringTrim(emailToValidate);
    var emailLength = emailToValidate.length;
    var atPos = emailToValidate.indexOf('@');
    var firstDotPos = emailToValidate.indexOf('.');
    var lastDotPos = emailToValidate.lastIndexOf('.');
    if (emailLength < 7) return(false);                // minimum email address length ("x@xx.xx")
    if (atPos < 1) return(false);                    // traps for no @, or @ as first character
    if (firstDotPos < 1) return(false);                // traps for no ., or . as first character
    if (atPos == emailLength-1) return(false);        // traps for @ as penultimate or last character
    if (lastDotPos >= emailLength-2) return(false);    // traps for too few digits after last . (must be at least 2)
    // traps for @ character next to . character
    if (emailToValidate.charAt(atPos-1) == '.' || emailToValidate.charAt(atPos+1) == '.') return(false);

I just find this sort of thing much easier to (a) understand and (b) modify without RegExp knowledge.

It may not be 100% effective against all email addresses, but will probably trap 99% of common mistakes (much like the RegExp version, IMHO).


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