function switchTag(tag,contents) 
{ 
    var tag_obj = document.getElementById("tags").getElementsByTagName("li");
	var taglength = tag_obj.length;
    for(i=1; i<=taglength; i++)     { 
        if ("tag"+i==tag){ 
            document.getElementById(tag).getElementsByTagName("a")[0].className="selectli"+i; 
            document.getElementById(tag).getElementsByTagName("a")[0].getElementsByTagName("span")[0].className="selectspan"+i; 
        }else{ 
            document.getElementById("tag"+i).getElementsByTagName("a")[0].className=""; 
            document.getElementById("tag"+i).getElementsByTagName("a")[0].getElementsByTagName("span")[0].className=""; 
        } 
        if ("contents"+i==contents){ 
            document.getElementById(contents).className=""; 
        }else{ 
            document.getElementById("contents"+i).className="hidecontents"; 
        } 
        document.getElementById("contents").className=contents; 
    } 
}