For JSON and script requests, set the scriptCharset before the url so IE won't...

For JSON and script requests, set the scriptCharset before the url so IE won't interpret it the wrong way; fixes #4855.

src/ajax.js

@@ -300,10 +300,10 @@ jQuery.extend({
 		if ( s.dataType === "script" && type === "GET" && remote ) {
 			var head = document.getElementsByTagName("head")[0] || document.documentElement;
 			var script = document.createElement("script");
-			script.src = s.url;
 			if ( s.scriptCharset ) {
 				script.charset = s.scriptCharset;
 			}
+			script.src = s.url;
 
 			// Handle Script loading
 			if ( !jsonp ) {