function is_array( mixed_var ) {
    // http://kevin.vanzonneveld.net
    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Legaev Andrey
    // +   bugfixed by: Cord
    // *     example 1: is_array(['Kevin', 'van', 'Zonneveld']);
    // *     returns 1: true
    // *     example 2: is_array('Kevin van Zonneveld');
    // *     returns 2: false
 
    return ( mixed_var instanceof Array );
}

function str_replace(search, replace, subject) {
    // http://kevin.vanzonneveld.net
    // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Gabriel Paderni
    // +   improved by: Philip Peterson
    // +   improved by: Simon Willison (http://simonwillison.net)
    // +    revised by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
    // -    depends on: is_array
    // *     example 1: str_replace(' ', '.', 'Kevin van Zonneveld');
    // *     returns 1: 'Kevin.van.Zonneveld'
    // *     example 2: str_replace(['{name}', 'l'], ['hello', 'm'], '{name}, lars');
    // *     returns 2: 'hemmo, mars'    
    
    var f = search, r = replace, s = subject;
    var ra = is_array(r), sa = is_array(s), f = [].concat(f), r = [].concat(r), i = (s = [].concat(s)).length;
 
    while(j = 0, i--){
        while(s[i] = s[i].split(f[j]).join(ra ? r[j] || "" : r[0]), ++j in f);
    }
     
    return sa ? s : s[0];
}

function test_email (my_email) {
        var new_string = new String(my_email);
        if (!new_string.match('^[-_\.0-9a-zA-Z]{1,}@[-_\.0-9a-zA-Z]{1,}[\.][0-9a-zA-Z]{2,}$')) {
                return false;
        }
        else {
                return true;
        }
    }