function validateForm(form) { //This is the name of the function

if (form.ContactName.value == "") { //This checks to make sure the field is not empty
   alert("Contact Name is Required."); //Informs user of empty field
   form.ContactName.focus( ); //This focuses the cursor on the empty field
   return false; //This prevents the form from being submitted
   }
   
if (form.Email.value == "") {
   alert("E-mail is Required.");
   form.Email.focus( );
   return false;
   }
   
if (echeck(form.Email.value)==false){
		form.Email.value=""
		form.Email.focus()
		return false
	}
	return true   
// you may copy the above 5 lines for each form field you wish to validate
// Replace the text "FIELD1" with the name you wish to call the field
}

function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid E-mail Address")
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid E-mail Address")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

 		 return true					
	}