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)
		return true;
	} else {
		return false;
	}
}