Javascript问题，我的div不会移动

Question

昨天我的老师在课堂上放了一些代码供我们在家测试，但我似乎无法使代码正常工作。 代码要做的是在按住鼠标的同时移动div。 我给我的朋友看了，我们认为问题出在这里：

calculator.style.top = getStyle(calculator, "top");
calculator.style.left = getStyle(calculator, "left");

function getStyle(object,styleName)
{
 if (window.getComputedStyle)
  {
    return document.defaultView.getComputedStyle(object, null).getPropertyValue(styleName);
  }
 else if (object.currentStyle)
   {
    return object.currentStyle[styleName];
   }
}

但是我们似乎仍然无法使其正常运行。 帮助将不胜感激。 另外，这里是完整的代码，以防万一您需要查看它：

diffx = null;
diffy = null;
off = document.getElementById("buttonOff");
on = document.getElementById("calcButton");
calculator = document.getElementById("calculator");
calculator.style.top = getStyle(calculator, "top");
calculator.style.left = getStyle(calculator, "left");

function getStyle(object,styleName)
{
 if (window.getComputedStyle)
  {
    return document.defaultView.getComputedStyle(object, null).getPropertyValue(styleName);
  }
 else if (object.currentStyle)
   {
    return object.currentStyle[styleName];
   }
}

function grabCalculator(e)
{
            var evt = e || window.event;
            calculator = evt.target || evt.srcElement;
            var mousex = evt.clientX;
            var mousey = evt.clientY;
            diffx = parseInt(calculator.style.left) – mousex;
            diffy = parseInt(calculator.style.top) – mousey;
            addEvent(document, "mousemove", moveCalculator, false);
            addEvent(document, "mouseup", dropCalculator, false);
}

function moveCalculator(e)
{
            var evt = e || window.event;
            var mousex = evt.clientX;
            var mousey = evt.clientY;
            calculator.style.left = mousex + diffx + "px";
            calculator.style.top = mousey + diffy + "px";
}

function addEvent(obj, eventType, fnName, cap)
{
            if (obj.attachEvent)
            {
                        obj.attachEvent("on" + eventType, fnName);
            }

            else
            {
                        obj.addEventListener(eventType, fnName, cap);
            }
}

function removeEvent(obj, eventType, fnName, cap)
{
            if (obj.attachEvent)
            {
                        obj.detachEvent("off" + eventType, fnName);
            }

            else
            {
                obj.removeEventListener(eventType, fnName, cap);
            }
}

function dropCalculator(e)
{
            removeEvent(document,"mousemove", moveCalculator, false);
            removeEvent(document, "mouseup", dropCalculator, false);
}

function main() {
    alert("TEST");
    //store top and left values of calculator
    calculator.style.top = getStyle(calculator, "top");
    calculator.style.left = getStyle(calculator, "left");
    calcButtonState = true;

}

window.onload = main;

再次感谢！ 桑德罗

---

编辑：添加了Jsfiddle链接： http : //jsfiddle.net/7225J/

（输出看起来也很可怕，因为它没有被调整为这么小的大小）

Answer 1

我认为您的问题出在grabCalculator函数中。 尝试更改：

diffx = parseInt(calculator.style.left) – mousex;
diffy = parseInt(calculator.style.top) – mousey;

至：

diffx = parseInt(calculator.offsetLeft) – mousex;
diffy = parseInt(calculator.offsetTop) – mousey;

也把它放在主要：

addEvent(..., grabCalculator, ...);

Answer 2

通常，将初始计算器坐标设置如下：

calculator.style.top = 0 + "px";
calculator.style.left = 0 + "px";

根本不要使用getStyle。 之后直接访问即可。 这将起作用，因为您将这两行放入了主行。