Caching array length instead of accessing it with each iteration. r=crschmidt (closes #1636)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7627 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Format/JSON.js

@@ -266,7 +266,7 @@ OpenLayers.Format.JSON = OpenLayers.Class(OpenLayers.Format, {
             var pieces = ['['];
             this.level += 1;
     
-            for(var i=0; i<array.length; ++i) {
+            for(var i=0, len=array.length; i<len; ++i) {
                 // recursive calls need to allow for sub-classing
                 json = OpenLayers.Format.JSON.prototype.write.apply(this,
                                                     [array[i], this.pretty]);