function checkEnter(e){
var characterCode;

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