function checkEnter(e){ //e is event object passed from function invocation
	var characterCode // literal character code will be stored in this variable
	
	if(e && e.which){ //if which property of event object is supported (NN4)
		e = e;
		characterCode = e.which; //character code is contained in NN4's which property
	}
	else{
		e = event
		characterCode = e.keyCode; //character code is contained in IE's keyCode property
	}
	
	if(characterCode == 13){ //if generated character code is equal to ascii 13 (if enter key)
		document.login.submit(); //submit the form
		return false;
	}
	else {
		return true;
	}
}