Revert "Ajax: Mitigate possible XSS vulnerability"

This reverts commit f60729f.

Fixes jquerygh-3011
Refs ad358fd

Author: mgol

src/ajax/script.js

@@ -4,13 +4,6 @@ define( [
 	"../ajax"
 ], function( jQuery, document ) {
 
-// Prevent auto-execution of scripts when no explicit dataType was provided (See gh-2432)
-jQuery.ajaxPrefilter( function( s ) {
-	if ( s.crossDomain ) {
-		s.contents.script = false;
-	}
-} );
-
 // Install script dataType
 jQuery.ajaxSetup( {
 	accepts: {

test/unit/ajax.js

@@ -85,44 +85,6 @@ QUnit.module( "ajax", {
 		};
 	} );
 
-	ajaxTest( "jQuery.ajax() - execute js for crossOrigin when dataType option is provided", 3,
-		function( assert ) {
-			return {
-				create: function( options ) {
-					options.crossDomain = true;
-					options.dataType = "script";
-					return jQuery.ajax( url( "data/script.php?header=ecma" ), options );
-				},
-				success: function() {
-					assert.ok( true, "success" );
-				},
-				complete: function() {
-					assert.ok( true, "complete" );
-				}
-			};
-		}
-	);
-
-	ajaxTest( "jQuery.ajax() - do not execute js (crossOrigin)", 2, function( assert ) {
-		return {
-			create: function( options ) {
-				options.crossDomain = true;
-				return jQuery.ajax( url( "data/script.php" ), options );
-			},
-			success: function() {
-				assert.ok( true, "success" );
-			},
-			fail: function() {
-				if ( jQuery.support.cors === false ) {
-					assert.ok( true, "fail" );
-				}
-			},
-			complete: function() {
-				assert.ok( true, "complete" );
-			}
-		};
-	} );
-
 	ajaxTest( "jQuery.ajax() - success callbacks (late binding)", 8, function( assert ) {
 		return {
 			setup: addGlobalEvents( "ajaxStart ajaxStop ajaxSend ajaxComplete ajaxSuccess", assert ),