function isEmail(argvalue) {
if (argvalue.indexOf(" ") != -1) return false
else if (argvalue.indexOf("@") == -1) return false
else if (argvalue.indexOf("@") == 0) return false 
else if (argvalue.indexOf("@") == (argvalue.length-1)) return false
 arrayString = argvalue.split("@");// (works only in netscape3 and above.) 
//var retSize = customSplit(argvalue, "@", "arrayString")
if (arrayString[1].indexOf(".") == -1) return false
else if (arrayString[1].indexOf(".") == 0) return false
else if (arrayString[1].charAt(arrayString[1].length-1) == ".") return false
return true
}