Want a transparent display

I would like to make a display to display a warning message. In fact, the HTML page was already sent and it is important that this framework is shown above (with a bit of transparency)

But I do not know whether to do this in css, javascript or something else!

The 2 are possible, you need to make a div (last element of the body) in CSS:

Code:

---

#maDiv {
  position: absolute; // to position above the rest;
  -moz-opacity: 0.5; // property of transparency (0 to 1) for old browsers
  opacity: 0.5; // property standard CSS 2 (and 3) for Firefox, IE8 and browser tt faithful to the W3C
  filter: alpha (opacity = 50) // for Internet Explorer 7 and - (if I am not mistaken)
}

---

Finally, there's not a worry but normally enough to continue ...

Because you think IE8 is true to the W3C?

Code:

---

-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";;

---

I think filter: alpha (opacity = 50); works very well in IE 8

Personally I hate IE, but I had read and heard that it was the standard (not on everything, but on the most stupid thing).