div浮动对话框，兼容firefox、opera、google浏览器

cMouseUpEvent = document.onmouseup;
    titleBar.onmousedown = function() {
        var evt = getEvent();
        moveable = true; 
        moveX = evt.clientX;
        moveY = evt.clientY;
        moveTop = parseInt(msgObj.style.top);
        moveLeft = parseInt(msgObj.style.left);
        
        document.onmousemove = function() {
            if (moveable) {
                var evt = getEvent();
                var x = moveLeft + evt.clientX - moveX;
                var y = moveTop + evt.clientY - moveY;
                if ( x > 0 &&( x + w < iWidth) && y > 0 && (y + h < iHeight) ) {
                    msgObj.style.left = x + "px";
                    msgObj.style.top = y + "px";
                }
            }    
        };
        document.onmouseup = function () { 
            if (moveable) { 
                document.onmousemove = docMouseMoveEvent;
                document.onmouseup = docMouseUpEvent;
                moveable = false; 
                moveX = 0;
                moveY = 0;
                moveTop = 0;
                moveLeft = 0;
            } 
        };
    }
    
    var closeBtn = tr.i