more clever prefix detection. (use unprefixed property when available.)

js/id/renderer/map.js

@@ -53,7 +53,7 @@ iD.Map = function() {
         class_fill = iD.Style.styleClasses('stroke'),
         class_area = iD.Style.styleClasses('area'),
         class_casing = iD.Style.styleClasses('casing'),
-        transformProp = iD.util.prefix(['webkit', 'ms', 'Moz']) + 'transform',
+        transformProp = iD.util.prefixProperty('Transform'),
         support3d = (function() {
             // test for translate3d support. Based on https://gist.github.com/3794226 by lorenzopolidori and webinista
             var el = document.createElement('div'),

js/id/util.js

@@ -72,6 +72,15 @@ iD.util.prefix = function(browsers) {
         return '';
     })(browsers);
 };
+iD.util.prefixProperty = function(property) {
+    prefixes = ['webkit', 'ms', 'Moz', 'O'];
+    return (function prefixMatch(p) { // via mbostock
+        var i = -1, n = p.length, s = document.body.style;
+        if (property.toLowerCase() in s) return property.toLowerCase();
+        while (++i < n) if (p[i] + property in s) return '-' + p[i].toLowerCase() + '-' + property.toLowerCase();
+        return '';
+    })(prefixes);
+};
 
 iD.util.geo = {};