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 ID")
	   return false
	}

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

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

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

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

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

	 return true					
}

function validateForm(form) { //This is the name of the function
if (form.emailaddress.value == "") { //This checks to make sure the field is not empty
   alert("An Email is required to process this form."); //Informs user of empty field
   form.emailaddress.focus( ); //This focuses the cursor on the empty field
   return false; //This prevents the form from being submitted
   }
   
if (echeck(form.emailaddress.value)==false){
	form.emailaddress.value=""
	form.emailaddress.focus()
	return false;
	}

// 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
}