Interactive Tab Menu doesnt work

So im using this right now:

       <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
        <html xmlns="http://www.w3.org/1999/xhtml">
        <HEAD>
        <TITLE></TITLE>
        <STYLE>
        #maincontent {
            width: 860px;
            position: relative;
            margin-bottom: 20px;
            margin-top: 40px;
            border-top-color: #CCC;
            border-right-color: #CCC;
            border-bottom-color: #CCC;
            border-left-color: #CCC;
            margin-right: auto;
            margin-left: auto;
        }
        #tabContents {
            vertical-align: top;
            padding-top: 5px;
            padding-right: 5px;
            padding-left: 5px;
            border-right-width: thin;
            border-bottom-width: thin;
            border-left-width: thin;
            border-right-style: solid;
            border-bottom-style: solid;
            border-left-style: solid;
            border-top-color: #336633;
            border-right-color: #336633;
            border-bottom-color: #336633;
            border-left-color: #336633;
            font-family: Verdana, Geneva, sans-serif;
            font-size: 12px;
            font-weight: normal;
            color: #21A54F;
            padding-bottom: 10px;
        }
        #TabHidden {
            position: absolute;
            width: 834px;
            left: 57px;
            top: 277px;
            height: 260px;
            clear: both;
            visibility: hidden;
            overflow: hidden;
        }
        #redirect {
            width: 746px;
            margin-left: 56px;
            margin-bottom: 15px;
            font-family: Verdana, Geneva, sans-serif;
            font-style: italic;
            color: #276B3F;
            font-size: 10px;
            text-align: center;
        }
        #TabDivPic {
            height: auto;
            width: 175px;
            margin-right: 30px;
            float: left;
        }
        .conts	{
            visibility:hidden
        }
        .tab	{
            font-family:Verdana, Geneva, sans-serif;
            font-size:10pt;
            text-align:center;
            font-weight:normal;
            color: #FFF;
            background-color: #21A54F;
            border-right-style: solid;
            border-left-style: solid;
            border-right-width: thin;
            border-left-width: thin;
            border-right-color: #CCC;
            border-left-color: #CCC;
        }
        .selTab	{
            font-weight:bold;
            text-align:center;
            font-family: Verdana, Geneva, sans-serif;
            color: #FFFFFF;
            background-color: #276B3F;
            font-size: 12px;
        }
        #tabstyle #td {
            font-family: Verdana, Geneva, sans-serif;
            font-size: 12px;
            color: #FFF;
        }
        #tabtable {
            width: 656px;
        }
        </STYLE>
        <SCRIPT language="javascript" type="text/javascript">
        
        //a public function that the container uses to pass in values for the labels
        function public_Labels(label1, label2, label3, label4, label5, label6, label7){
            
            t1.innerText = label1;
            t2.innerText = label2;
            t3.innerText = label3;
            t4.innerText = label4;
            t5.innerText = label5;
            t6.innerText = label6;
            t7.innerText = label7;
        }
        
        //a public function that the container uses to pass in values for the card containers
        function public_Contents(contents1, contents2, contents3, contents4, contents5, contents6, contents7){
        
            t1Contents.innerHTML = contents1;
            t2Contents.innerHTML = contents2;
            t3Contents.innerHTML = contents3;
            t4Contents.innerHTML = contents4;
            t5Contents.innerHTML = contents5;
            t6Contents.innerHTML = contents6;
            t7Contents.innerHTML = contents7;
        
            init();
        }
        
        //sets the default display to tab 1
        function init(){
            tabContents.innerHTML = t1Contents.innerHTML;
        }	
        
        //this is the tab switching function
        var currentTab;
        var tabBase;
        var firstFlag = true;
        
        
        function changeTabs(event){
        
            if(firstFlag == true){
                currentTab = t1;
                tabBase = t1base;
                firstFlag = false;
            }
        
            if(event.target.className == "tab"){
        
                currentTab.className = "tab";
        
                tabBase.style.backgroundColor = "white";
        
                currentTab = event.target;
        
                tabBaseID = currentTab.id + "base";
        
                tabContentID = currentTab.id + "Contents";
        
                tabBase = document.getElementById(tabBaseID);
        
                tabContent = document.getElementById(tabContentID);
        
                currentTab.className = "selTab";
                
                tabBase.style.backgroundColor = "";
        
                tabContents.innerHTML = tabContent.innerHTML;
        
            }
        }
        
        </SCRIPT>
        </HEAD>
        <BODY>
        <div id="maincontent">
        <DIV STYLE="position:relative; top:0px; height:400; width:746px; left:56px; border:none thin gray" onClick="changeTabs(event)" onload="init()">
        <TABLE id="tabtable" CELLPADDING=0 CELLSPACING=0>
            <TR id="tabstyle">
                <TD ID=t1 CLASS=selTab HEIGHT=25>TAB ONE</TD>
                <TD ID=t2 CLASS=tab>TAB TWO</TD>
                <TD ID=t3 CLASS=tab>TAB THREE</TD>
                <TD ID=t4 CLASS=tab>TAB FOUR</TD>
                <TD ID=t5 CLASS=tab>TAB FIVE</TD>
                <TD ID=t6 CLASS=tab>TAB SIX</TD>
                <TD ID=t7 CLASS=tab>TAB SEVEN</TD>
            </TR>
            <TR>
                <TD ID=t1base STYLE="height:2; border-left:solid thin white"></TD>
                <TD ID=t2base STYLE="height:2; background-color:white"></TD>
                <TD ID=t3base STYLE="height:2; background-color:white"></TD>
                <TD ID=t4base STYLE="height:2; background-color:white"></TD>
                <TD ID=t5base STYLE="height:2; background-color:white"></TD>
                <TD ID=t6base STYLE="height:2; background-color:white"></TD>
                <TD ID=t7base STYLE="height:2; background-color:white; border-right:solid thin white"></TD>	
            </TR>
        
        
            <TR>
                <TD HEIGHT="*" COLSPAN=7 ID=tabContents>
                content<br>
                content<br>
                content<br>
                content<br>
        
        </TD>
        
            </TR>
        </TABLE>
        </DIV>
          <div id="TabHidden">
          <DIV CLASS=conts ID=t1Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t2Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t3Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t4Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t5Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t6Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        
          <DIV CLASS=conts ID=t7Contents>
                content<br>
                content<br>
                content<br>
                content<br>
          </DIV>
        </div>
        </DIV>
        </BODY>
        </HTML>

The tab works perfectly fine for Chrome and IE. But doesnt work for Fire Fox. Need help
sorry if its messy, first time using this forum

Hi enomi. Welcome to the forums. :slight_smile:

That code actually works fine in Firefox for me (on Mac). Are you testing this on a PC?

Yes. i am on a pc right now

Its been solved. I updated firefox at the office and it works fine. Appreciate the reply and the welcome ralph. cheers

No probs. Glad it’s sorted. :slight_smile: