Javascript setting timeout problem

[Kong Chun Ho]

Hello,

I have a problem on setting timeout in for loop.

Here is my code:

function setOpacity (elem, val) {
var z = document.getElementById(elem);
z.style.opacity=val/100;
z.style.filter = "alpha(opacity=" + val + ")";
}
function LiveSupport() {
var x = document.getElementById('c_cover');
var y = document.getElementById('c_popcontent');
var z;
var startOpacity = '0'; //int only
var endOpacity = '70'; //int only
var nowOpacity;
var t = 0;
x.style.position = 'absolute';
x.style.top = '80px';
x.style.left = '50%';
x.style.marginLeft = '-325px';
x.style.background = '#000';
x.style.zIndex = '998';
x.style.height = '676px';
x.style.width = '650px';
x.style.opacity=startOpacity/100;
x.style.filter = "alpha(opacity=" + startOpacity + ")";
for (z=startOpacity; z!=endOpacity; z++) {
t++;
setTimeout("setOpacity('c_cover', z);", t);
}
}
 

When i run "LiveSupport();", i have received "z is not defined" error!

How to fix it?

Thanks

[Dormilich]

that’s right. "setOpacity('c_cover', z);" is not executed in the scope of LiveSupport() but of setTimeout()/window. thus it is not defined. you would have to use a Closure for that.

// untested
setTimeout(function(){ setOpacity('c_cover', z); }, t);

[Kong Chun Ho]

ok thanks, it works!