// Key Event Helpers
function addKeyDownHandler(source, callback){
	nn=(document.layers)?true:false; 
	ie=(document.all)?true:false; 

	source.onkeydown=callback; 
	if(nn) document.captureEvents(Event.KEYDOWN);
}

function addKeyUpHandler(source, callback){
	nn=(document.layers)?true:false; 
	ie=(document.all)?true:false; 

	source.onkeyup=callback; 
	if(nn) document.captureEvents(Event.KEYUP);
}

function addKeyPressHandler(source, callback){
	nn=(document.layers)?true:false; 
	ie=(document.all)?true:false; 

	source.onkeypress=callback; 
	if(nn) document.captureEvents(Event.KEYPRESS);
}

function isKeyPressed(e, charCode) {

	var evt=(e) ? e :(window.event)? window.event:null; 
	if (evt) { 
		var key=(evt.charCode) ? evt.charCode : ((evt.keyCode)?evt.keyCode:((evt.which)?evt.which:0)); 
		return key==charCode; 
	} 
}

function isEnterKeyPressed(e) {
    
	var evt=(e) ? e :(window.event)? window.event:null; 

	if (evt) { 
		var key=(evt.charCode) ? evt.charCode : ((evt.keyCode)?evt.keyCode:((evt.which)?evt.which:0)); 
		return key==13; 
	} 
	return false;
}

function blockEnterKey(sourceControl){
	addKeyPressHandler(sourceControl, enterKeyPressBlocker);
}

function enterKeyPressBlocker(e){
	if (isKeyPressed(e, '13')){
		return false;
	}
}