function jah_switch(url,target)
{

    if (document.getElementById(target).innerHTML != '')
    {
        document.getElementById(target).innerHTML = '';
    }
    else
    {

        jah(url,target);
    }

}
function jah(url,target) {
    // native XMLHttpRequest object
    document.getElementById(target).innerHTML = '';
    if (jah!='') {
	    if (window.XMLHttpRequest) {
	        req = new XMLHttpRequest();
	        req.onreadystatechange = function() {jahDone(target);};
	        req.open("GET", url);
	       	req.setRequestHeader('Cache-Control', 'no-cache'); 
	        req.send(null);
	    // IE/Windows ActiveX version
	    } else if (window.ActiveXObject) {
	        req = new ActiveXObject("Microsoft.XMLHTTP");
	        if (req) {
	            req.onreadystatechange = function() {jahDone(target);};
	            req.open("GET", url, true);
	            req.setRequestHeader('Cache-Control', 'no-cache'); 
	             req.send();
	        }
	    }
	  }
}    

function jahDone(target) {
    // only if req is "loaded"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            
            results = req.responseText;
            document.getElementById(target).innerHTML = results;
        } else {
            document.getElementById(target).innerHTML="jah error:\n" +
                req.statusText;
        }
    }
}