allow opacity to be set with OpenLayers.Util.modifyDOMElement(). added test.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@1547 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -14,9 +14,10 @@ OpenLayers.Util = new Object();
  * @param {String} position
  * @param {String} border
  * @param {String} overflow
+ * @param {float} opacity Fractional value (0.0 - 1.0)
  */
 OpenLayers.Util.modifyDOMElement = function(element, id, px, sz, position, 
-                                            border, overflow) {
+                                            border, overflow, opacity) {
 
     if (id) {
         element.id = id;
@@ -38,6 +39,10 @@ OpenLayers.Util.modifyDOMElement = function(element, id, px, sz, position,
     if (overflow) {
         element.style.overflow = overflow;
     }
+    if (opacity) {
+        element.style.opacity = opacity;
+        element.style.filter = 'alpha(opacity=' + (opacity * 100) + ')';
+    }
 };
 
 /**