[BUGFIX] Replace the usage of the onLoad event

Fixes: #29194


git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/pmkshadowbox/trunk@76533 735d13b6-9817-0410-8766-e36946ffe9aa

static/PMK_Shadowbox/setup.txt

@@ -100,17 +100,12 @@ page.headerData.1233 {
 	40 = TEXT
 	40 {
 		value (
-			function shadowBoxSetup() {
+			Shadowbox.onReady = function() {
 				var shadowBoxElements = document.getElementsByTagName('area');
 				if (shadowBoxElements.length) {
 					Shadowbox.setup(shadowBoxElements, {$plugin.pmkshadowbox.imageMapOptions});
 				}
 			}
-			if (window.addEventListener) {
-				window.addEventListener('load', shadowBoxSetup, false);
-			} else if (window.attachEvent) {
-				window.attachEvent('onload', shadowBoxSetup);
-			}
 		)
 
 		override = ;