// JavaScript Document
	//precarga de imagenes
	if (document.images){
		foto1 = new Image();
		foto1.src = "../img/tximitxb.jpg";
		foto2 = new Image();
		foto2.src = "../img/casablanca.jpg";
		foto3 = new Image();
		foto3.src = "../img/osaki.gif";
	}
	
	function opacity(id, opacStart, opacEnd, millisec) {
		//speed for each frame
		var speed = Math.round(millisec / 100);
		var timer = 0;
	
		//determine the direction for the blending, if start and end are the same nothing happens
		if(opacStart > opacEnd) {
			for(i = opacStart; i >= opacEnd; i--) {
				setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
				timer++;
			}
		} else if(opacStart < opacEnd) {
			for(i = opacStart; i <= opacEnd; i++)
				{
				setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
				timer++;
			}
		}
	}
	
	//change the opacity for different browsers
	function changeOpac(opacity, id) {
		var object = document.getElementById(id).style; 
		object.opacity = (opacity / 100);
		object.MozOpacity = (opacity / 100);
		object.KhtmlOpacity = (opacity / 100);
		object.filter = "alpha(opacity=" + opacity + ")";
	}
	
	function shiftOpacity(id, millisec) {
		//if an element is invisible, make it visible, else make it invisible
		if(document.getElementById(id).style.opacity == 0) {
			opacity(id, 0, 100, millisec);
		} else {
			opacity(id, 100, 0, millisec);
		}
	}
	
	function blendimage(divid, imageid, imagefile, imagAlt, millisec) {
		var speed = Math.round(millisec / 100);
		var timer = 0;
		
		//set the current image as background
		document.getElementById(divid).style.backgroundImage = "url(../img/ezerez.gif)";
		
		//make image transparent
		changeOpac(0, imageid);
		
		//make new image
		document.getElementById(imageid).src = imagefile;
		//atributo 'alt' de la imagen al pasar por encima
		document.getElementById(imageid).alt = imagAlt;
	
		//fade in image
		for(i = 0; i <= 100; i++) {
			setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
			timer++;
		}
	}
	
	function currentOpac(id, opacEnd, millisec) {
		//standard opacity is 100
		var currentOpac = 100;
		
		//if the element has an opacity set, get it
		if(document.getElementById(id).style.opacity < 100) {
			currentOpac = document.getElementById(id).style.opacity * 100;
		}
	
		//call for the function that changes the opacity
		opacity(id, currentOpac, opacEnd, millisec)
	}