virt2/api/soft/fm/style/opacity.js

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/*
* This nice script fades in and out using CSS and JS
*
* http://www.brainerror.net/scriptsscripts_blendtrans.php
*/
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 + ")";
}
// When working with multiple opacities you might notice that you
// cannot always know the starting opacity when writing the page.
// To get arround this I created the function currentOpac(),
// it simply retrieves the current opacity of an element and then fades from that.
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)
}