Onclick not working with ben alman's jQuery BBQ

Onclick not working with ben alman's jQuery BBQ

Hi
 
New to all this so ill try asking you guys.
 
Im creating a ajax based page so i needed to use jquery to fix the back button.
Found Ben alman's BBQ library and it works perfectly, almost. :P
 
The problem is that when i use onclick to run an ajax function. It doesnt work untill i have refreshed the page.
The two doesnt seem to work together :S 
 
Why is this? Is this suppose to happen or? 
 
The function that im trying to run on onclick is this
 
 
function xmlhttpPost(strURL, input_value) {
    var xmlHttpReq = false;
    var self = this;
  
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    }
    self.xmlHttpReq.open('POST', strURL, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.onreadystatechange = function() {
        if (self.xmlHttpReq.readyState == 4) {
            updatepage(self.xmlHttpReq.responseText);
        }
    }
    self.xmlHttpReq.send(getquerystring(input_value));
}
















function getquerystring(input_value) {
    qstr = 'w=' + escape(input_value);  // NOTE: no '?' before querystring
    return qstr;
}


function updatepage(str){
    document.getElementById("result").innerHTML = str;
}

 
Any help would be appreciated :)