javascript - 拖动时光标变回工字梁

Question

我的代码如下。我也有它在 http://jsfiddle.net/S2JHa/

我不明白为什么当我点击鼠标并将鼠标拖到我的图片上时，光标会变成 I 型。

如果我删除“一些文本”，那么它不会改变。这发生在 Chrome 中。 FF 很好。

如果您能告诉我如何修复，我将不胜感激。谢谢!

<div id="window">
    <div>some text</div>
  <div id="sketch" class="box">
    <div class="contents">
      <canvas id="image-layer"></canvas>
    </div>
  </div>
</div>
​

CSS:

#window #sketch
{
    padding: 1cm 0;
}
#window #sketch canvas
{
    left: 0;
    position: absolute;
    top: 0;
}
#window #sketch .contents
{
    cursor: crosshair;
    position: relative;
}
div.box
{
    background-color: #fff;
    border: 1px solid black;
    border-radius: 0.3cm;
    cursor: move;
    left: 0;
    position: fixed;
    top: 0;
}
​

JavaScript:

function image_onload(e) {
    var image = e.target;

    $("div.box").draggable({
        cancel: "div.box div.contents",
        containment: "document"
    });

    var x = $("#window #sketch");

    // size to fit image
    x.css("width", image.width);
    x.css("height", image.height);

    // center sketch inside parent window
    x.css("left", ($(window).width() - x.width()) / 2);

    var canvas = document.getElementById("image-layer");

    canvas.height = image.height;
    canvas.width = image.width;

    var context = canvas.getContext("2d");
    context.drawImage(image, 0, 0);
}

function open(url) {
    var image = new Image();

    image.src = url;
    image.onload = image_onload;
}

open("http://upload.wikimedia.org/wikipedia/commons/6/63/Wikipedia-logo.png");

Answer 1

如果您不想与 Canvas 交互，您可以像这样取消 onmousedown 事件:

canvas.onmousedown = function () {
    return false;
}

对于 IE，您将需要:

canvas.onselectstart = function () { 
    return false;
}

请在此处查看更新的 jsfiddle:http://jsfiddle.net/S2JHa/11/