function isEmail(str)

{

// are regular expressions supported?

var supported = 0;

if (window.RegExp) {

var tempStr = "a";

var tempReg = new RegExp(tempStr);

if (tempReg.test(tempStr)) supported = 1;

}

if (!supported)

return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);

var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");

var r2 = new RegExp("^.+\\@(\\[?)][a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");

return (!r1.test(str) && r2.test(str));

}