Switch to sequential ID numbering. Fixes #226.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@2645 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -622,6 +622,8 @@ OpenLayers.Util.getArgs = function(url) {
     return args;
 }
 
+OpenLayers.Util.lastSeqID = 0;
+
 /**
  * @param {String} prefix String to prefix random id. If null, default
  *                         is "id_"
@@ -633,7 +635,8 @@ OpenLayers.Util.createUniqueID = function(prefix) {
     if (prefix == null) {
         prefix = "id_";
     }
-    return prefix + Math.round(Math.random() * 10000);        
+    OpenLayers.Util.lastSeqID += 1; 
+    return prefix + OpenLayers.Util.lastSeqID;        
 };
 
 /** Constant inches per unit