element.style.opacity -= .05 why can't I do that?

in General Discussion edited January 2014
I'm a JavaScript newbie.

element.style.opacity -= .05

That doesn't seem to work at all. It doesn't work with parseFloat either. Below is my whole function.

#Layer1 {



function fadeOut (elId) {

\tel = document.getElementById(elId)

\tel.style.opacity = parseFloat(el.style.opacity) - .5


<a href="#" onclick="fadeOut('Layer1')">here</a>

What am I doing wrong?

Of course, element.style.opacity = .5 works fine...but I want to set the opacity relative to what it is currently.

Also, alert(element.style.opacity) returns a blank alert, even though the opacity is CLEARLY set to 1 at the start.




  • Reply 1 of 1
    This is actually more of CSS problem, and it is because CSS's design. Objects inherit their properties from their parents, and for some reason opasity is locked to between 0-100%, so when parent object has opacity set, you can only increase it, but not reduce it. Don't ask me why is it so, it just is.
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