function createXMLHttp(){
    if (window.XMLHttpRequest) {
        xmlHttp = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
}

function isAjax(obj) {
    if (obj.readyState == 4) {
        if (obj.status == 200) {
            return true;
        } else {
            return false;
        }    

    }
}

function calculateOffsetTop(field) {
    return calculateOffset(field, "offsetTop");
}

function calculateOffset(field, attr) {
    var offset = 0;
    while(field) {
        offset += field[attr];
        field = field.offsetParent;
    }
    
    return offset;
}

function createCell(data, classname) {
    var cel = document.createElement("td");
    var textNode = document.createTextNode(data);
    cel.appendChild(textNode);

    if (classname != null) {
        cel.setAttribute("className",classname);
    }
  
    return cel;
}

function clearDataTable(obj){
    var ind = obj.childNodes.length;
        
    if (ind != null && ind > 0){
        for (var i = ind -1; i >= 0; i--) {
            obj.removeChild(obj.childNodes[i]);
        }
    }
}