why css opacity effect not working in chrome?

.overlayupload {
  background-color: black;
  position: fixed;
  top: 0; right: 0; bottom: 0; left: 0;
  opacity: 0.4; /* also -moz-opacity, etc. */
  -webkit-opacity: 0.4;
  z-index: 10;
}

Above is the css that am using to overlay an transperent div while doing some processing and making the screen disable..but this only works in mozila..i want to make it works in chrome too..so can any one please tell me how can i do that?

Following is the div..

<div class="overlayupload" id="uploadprogress"
                        style="display: none"></div>