function preload(imgObj,imgSrc) {
	if (document.images) {
		eval(imgObj+' = new Image()')
		eval(imgObj+'.src = "'+imgSrc+'"')
	}
}

function changeImage(layer,imgName,imgObj) {
	if (document.images) {
		if (document.layers && layer!=null) {
			eval('var w=document.'+layer+'.document.images["'+imgName+'"].width')
			eval('var h=document.'+layer+'.document.images["'+imgName+'"].height')
			eval('document.'+layer+'.document.images["'+imgName+'"].src = '+imgObj+'.src')
			eval('document.'+layer+'.document.images["'+imgName+'"].width = w')
			eval('document.'+layer+'.document.images["'+imgName+'"].height = h')
			}
		else {
			var w=document.getElementById(imgName).width;
			var h=document.getElementById(imgName).height;	
			document.getElementById(imgName).src = eval(imgObj+".src");
			document.getElementById(imgName).width = w;
			document.getElementById(imgName).height = h;
			}
	}
}

function removeImage(layer,imgName){
	if (document.images) {
		if (document.layers && layer!=null) 
			eval('document.'+layer+'.document.images["'+imgName+'"].width = 0');
		else document.images[imgName].width = 0;
	}
}

function cambiaImagen(imgName,imgObj){
	changeImage(null,imgName,imgObj);
}

function cambiaImagenTable(imgName,imgObj,hand){
	if (hand==1)
		document.getElementById(imgName).style.cursor='hand'
	else document.getElementById(imgName).style.cursor='auto'
		document.getElementById(imgName).style.background = "url(" + eval(imgObj + ".src") +")";	
} 

function eliminaImagen(imgName){
	removeImage(null,imgName);
}

function mostrarLayer(layerName) {
	if (document.layers) 
            layerName.visibility="visible";     
	else 
            layerName.visibility="visible";  
  }

function ocultarLayer(layerName){
	if (document.layers) 
            layerName.visibility ="hide"; 
	else 
            layerName.visibility = "hidden"
    
}