var numberOfChars = 28; 

var isInvalid = new e_makeArray(numberOfChars); 
var InvalidChars = new e_makeArray(numberOfChars); 

function InvalidEmail(emailaddress) { 

	var temp = emailaddress; 
	temp = temp.toLowerCase(); 

	InvalidChars[1] = "'"; 
	InvalidChars[2] = "\""; 
	InvalidChars[3] = "\\"; 
	InvalidChars[4] = "/"; 
	InvalidChars[5] = "`"; 
	InvalidChars[6] = ","; 
	InvalidChars[7] = ";"; 
	InvalidChars[8] = ":"; 
	InvalidChars[9] = "|"; 
	InvalidChars[10] = "?"; 
	InvalidChars[11] = "<"; 
	InvalidChars[12] = ">"; 
	InvalidChars[13] = "["; 
	InvalidChars[14] = "]"; 
	InvalidChars[15] = "{"; 
	InvalidChars[16] = "}"; 
	InvalidChars[17] = "("; 
	InvalidChars[18] = ")"; 
	InvalidChars[19] = "="; 
	InvalidChars[20] = "+"; 
	InvalidChars[21] = "!"; 
	InvalidChars[22] = "#"; 
	InvalidChars[23] = "$"; 
	InvalidChars[24] = "%"; 
	InvalidChars[25] = "^"; 
	InvalidChars[26] = "&"; 
	InvalidChars[27] = "*"; 
	InvalidChars[28] = " "; 

	var dotPosition = temp.indexOf("."); 
	if (dotPosition < 0) { alert("Missing the dot in your email address."); return true; }

	var atPosition = temp.indexOf("@"); 
	if (atPosition < 0) { alert("Missing the @ sign in your email address."); return true; }

	for (var j = 1; j <= numberOfChars; j++) { 
		isInvalid[j] = temp.indexOf(InvalidChars[j]); 
	} 

	for (var j = 1; j <= numberOfChars; j++) { 
		if (isInvalid[j] != -1) { 
			alert("Invalid character in email: "+InvalidChars[j]); 
			return true;
			j = numberOfChars + 1;
		}
	} 
   return false; 
} 

function e_makeArray(n) { 
   this.length = n 
   for (var i = 1; i<=n; i++) { 
       this[i] = new String(); 
   } 
   return this; 
}