Index: alt_main.php
===================================================================
--- alt_main.php	(revision 352)
+++ alt_main.php	(working copy)
@@ -122,6 +122,22 @@
 		$pageModule = t3lib_BEfunc::isModuleSetInTBE_MODULES($newPageModule) ? $newPageModule : 'web_layout';
 
 		$this->mainJScode='
+		//browsercheck...
+	function GL_checkBrowser(){	//
+		this.dom= (document.getElementById);
+		this.op=  (navigator.userAgent.indexOf("Opera")>-1);
+		this.op7=  this.op && (navigator.appVersion.indexOf("7")>-1);  // check for Opera version 7
+		this.konq=  (navigator.userAgent.indexOf("Konq")>-1);
+		this.ie4= (document.all && !this.dom && !this.op && !this.konq);
+		this.ie5= (document.all && this.dom && !this.op && !this.konq);
+		this.ns4= (document.layers && !this.dom && !this.konq);
+		this.ns5= (!document.all && this.dom && !this.op && !this.konq);
+		this.ns6= (this.ns5);
+		this.bw=  (this.ie4 || this.ie5 || this.ns4 || this.ns6 || this.op || this.konq);
+		return this;
+	}
+	bw= new GL_checkBrowser();
+
 	/**
 	 * Function similar to PHPs  rawurlencode();
 	 */
@@ -305,17 +321,22 @@
 			var HLclass = mainModule ? "c-mainitem-HL" : "c-subitem-HL";
 		}
 
+		if (bw.ie5) {
+			var classNameLabel = "className";
+		} else {
+			var classNameLabel = "class";
+		}
+
 		if (docObj)	{
 				// Reset old:
 			if (currentlyHighLightedId && docObj.getElementById(currentlyHighLightedId))	{
-				docObj.getElementById(currentlyHighLightedId).attributes.getNamedItem("class").nodeValue = currentlyHighLighted_restoreValue;
+				docObj.getElementById(currentlyHighLightedId).setAttribute(classNameLabel, currentlyHighLighted_restoreValue);
 			}
 				// Set new:
 			currentlyHighLightedId = trId;
 			if (currentlyHighLightedId && docObj.getElementById(currentlyHighLightedId))	{
-				var classAttribObject = docObj.getElementById(currentlyHighLightedId).attributes.getNamedItem("class");
-				currentlyHighLighted_restoreValue = classAttribObject.nodeValue;
-				classAttribObject.nodeValue = HLclass;
+				currentlyHighLighted_restoreValue = docObj.getElementById(currentlyHighLightedId).getAttribute(classNameLabel);
+				docObj.getElementById(currentlyHighLightedId).setAttribute(classNameLabel, HLclass);
 			}
 		}
 	}
Index: template.php
===================================================================
--- template.php	(revision 352)
+++ template.php (working copy)
@@ -1805,6 +1805,27 @@
 				var DTM_array = new Array();
 				var DTM_origClass = new String();
 
+				function GL_checkBrowser(){	//
+					this.dom= (document.getElementById);
+					this.op=  (navigator.userAgent.indexOf("Opera")>-1);
+					this.op7=  this.op && (navigator.appVersion.indexOf("7")>-1);  // check for Opera version 7
+					this.konq=  (navigator.userAgent.indexOf("Konq")>-1);
+					this.ie4= (document.all && !this.dom && !this.op && !this.konq);
+					this.ie5= (document.all && this.dom && !this.op && !this.konq);
+					this.ns4= (document.layers && !this.dom && !this.konq);
+					this.ns5= (!document.all && this.dom && !this.op && !this.konq);
+					this.ns6= (this.ns5);
+					this.bw=  (this.ie4 || this.ie5 || this.ns4 || this.ns6 || this.op || this.konq);
+					return this;
+				}
+				bw= new GL_checkBrowser();
+
+				if (bw.ie5) {
+					var classNameLabel = "className";
+				} else {
+					var classNameLabel = "class";
+				}
+
 					// if tabs are used in a popup window the array might not exists
 				if(!top.DTM_currentTabs) {
 					top.DTM_currentTabs = new Array();
@@ -1816,7 +1837,7 @@
 						for(cnt = 0; cnt < DTM_array[idBase].length ; cnt++)	{
 							if (DTM_array[idBase][cnt] != idBase+"-"+index)	{
 								document.getElementById(DTM_array[idBase][cnt]+"-DIV").style.display = "none";
-								document.getElementById(DTM_array[idBase][cnt]+"-MENU").attributes.getNamedItem("class").nodeValue = "tab";
+								document.getElementById(DTM_array[idBase][cnt]+"-MENU").setAttribute(classNameLabel, "tab");
 							}
 						}
 					}
@@ -1826,7 +1847,7 @@
 						if (doToogle && document.getElementById(idBase+"-"+index+"-DIV").style.display == "block")	{
 							document.getElementById(idBase+"-"+index+"-DIV").style.display = "none";
 							if(DTM_origClass=="") {
-								document.getElementById(idBase+"-"+index+"-MENU").attributes.getNamedItem("class").nodeValue = "tab";
+								document.getElementById(idBase+"-"+index+"-MENU").setAttribute(classNameLabel, "tab");
 							} else {
 								DTM_origClass = "tab";
 							}
@@ -1834,7 +1855,7 @@
 						} else {
 							document.getElementById(idBase+"-"+index+"-DIV").style.display = "block";
 							if(DTM_origClass=="") {
-								document.getElementById(idBase+"-"+index+"-MENU").attributes.getNamedItem("class").nodeValue = "tabact";
+								document.getElementById(idBase+"-"+index+"-MENU").setAttribute(classNameLabel, "tabact");
 							} else {
 								DTM_origClass = "tabact";
 							}
@@ -1848,7 +1869,7 @@
 						if (document.getElementById(idBase+"-"+index+"-DIV").style.display == "block")	{
 							document.getElementById(idBase+"-"+index+"-DIV").style.display = "none";
 							if(isInit) {
-								document.getElementById(idBase+"-"+index+"-MENU").attributes.getNamedItem("class").nodeValue = "tab";
+								document.getElementById(idBase+"-"+index+"-MENU").setAttribute(classNameLabel, "tab");
 							} else {
 								DTM_origClass = "tab";
 							}
@@ -1856,7 +1877,7 @@
 						} else {
 							document.getElementById(idBase+"-"+index+"-DIV").style.display = "block";
 							if(isInit) {
-								document.getElementById(idBase+"-"+index+"-MENU").attributes.getNamedItem("class").nodeValue = "tabact";
+								document.getElementById(idBase+"-"+index+"-MENU").setAttribute(classNameLabel, "tabact");
 							} else {
 								DTM_origClass = "tabact";
 							}
@@ -1866,12 +1887,12 @@
 				}
 
 				function DTM_mouseOver(obj) {	//
-						DTM_origClass = obj.attributes.getNamedItem(\'class\').nodeValue;
-						obj.attributes.getNamedItem(\'class\').nodeValue += "_over";
+					DTM_origClass = obj.getAttribute(classNameLabel);
+					obj.setAttribute(classNameLabel, DTM_origClass+"_over"); 
 				}
 
 				function DTM_mouseOut(obj) {	//
-						obj.attributes.getNamedItem(\'class\').nodeValue = DTM_origClass;
+						obj.setAttribute(classNameLabel, DTM_origClass);
 						DTM_origClass = "";
 				}