function enableTooltips() {

        var h = document.createElement("span");
        h.id = "btc";
        h.setAttribute("id", "btc");
        h.style.position = "absolute";
        document.getElementsByTagName("body")[0].appendChild(h);
    
        var links = getElementsByClassName("tooltip_link");
        for (var i = 0; i < links.length; i++) {
            prepare(links[i]);
        }
    }
    
    function prepare( el ) {
       var list = getElementsByClassName("tooltip", el);
       var tooltip = list[0];
       el.tooltip = tooltip;
       el.onclick = showTooltip;
	// el.onmouseout = hideTooltip;
    }
  
    function showTooltip(e) {
       this.tooltip.style.display = 'block';
       document.getElementById("btc").appendChild(this.tooltip);
       Locate(e);
    }
	
    
    function hideTooltip(e) {
       this.tooltip.style.display = 'none';
       var d = document.getElementById("btc");
       if (d.childNodes.length > 0) d.removeChild(d.firstChild);
    }
	
	function hideTooltip2() {
       this.tooltip.style.display = 'none';
       var d = document.getElementById("btc");
       if (d.childNodes.length > 0) d.removeChild(d.firstChild);
    }
	
	function Locate(e) {
       var posx = 0,posy = 0;
       if (e == null) e = window.event;
       if (e.pageX || e.pageY) {
           posx = e.pageX;
           posy = e.pageY;
       }
       else if (e.clientX || e.clientY) {
           if (document.documentElement.scrollTop) {
               posx = e.clientX + document.documentElement.scrollLeft;
               posy = e.clientY + document.documentElement.scrollTop;
           }
           else {
               posx = e.clientX + document.body.scrollLeft;
               posy = e.clientY + document.body.scrollTop;
           }
       }
       document.getElementById("btc").style.top = (posy ) + "px";
       document.getElementById("btc").style.left = (posx - 100) + "px";
    }
    
    function getElementsByClassName(classname, node)  {
        if(!node) node = document.getElementsByTagName("body")[0];
        var a = [];
        var re = new RegExp('\\b' + classname + '\\b');
        var els = node.getElementsByTagName("*");
        for(var i=0,j=els.length; i<j; i++)
            if(re.test(els[i].className))a.push(els[i]);
        return a;
    }