代码可以在jsfiddle中使用，但不能在浏览器中使用

debugcn 发表于 Dev

用户名

这是我的HTML5代码。每当我尝试运行此文件时，我都会得到一个黑色的画布，里面没有矩形。但是它在jsfiddle中完美无瑕地工作。

<!DOCTYPE html>
<html>
<head>
<title>TEST</title>
<style>
body {
background-color:ivory;
}
#canvas {
border:10px solid red;
background-color:black;
}
 </style>
</head>
<body>
<canvas id="canvas" width="400" height="300">
</canvas>
<script type="text/javascript">
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
var $canvas = $("#canvas");
var canvasOffset = $canvas.offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var scrollX = $canvas.scrollLeft();
var scrollY = $canvas.scrollTop();

var isDown = false;
var startX;
var startY;

var toggle=0;
    var x=150;
    var y=100;
    var w=100;
    var h=100;
    var wasInside=false;

ctx.fillStyle = "#04B45F";
ctx.fillRect(x, y, w, h);

function changeColor() {
if (toggle == 0) {
    ctx.fillStyle = "#FFFFFF";
    toggle = 1;
} else {
    ctx.fillStyle = "#04B45F";
    toggle = 0;
}
ctx.fillRect(x, y, w, h);
}
function handleMouseMove(e) {

e.preventDefault();
var mx = parseInt(e.clientX - offsetX);
var my = parseInt(e.clientY - offsetY);

var isInsideNow = (mx > x && mx < x + w && my > y && my <= y + h);

if (isInsideNow && !wasInside) {
    changeColor();
    wasInside = true;
} else if (!isInsideNow && wasInside) {
    wasInside = false;
}

}

$("#canvas").mousemove(function (e) {
handleMouseMove(e);
});

</script>
</body>
</html>

这是jsfiddle的链接http://jsfiddle.net/9GcbH/4/。我在系统中使用了确切的代码。但这对我不起作用。我可以知道确切的原因以及如何克服它吗？

盖坦·盖瓦（Chetan Gawai）

试试这个

<!DOCTYPE html>
<html>
<head>
<title>TEST</title>
<style>
body {
background-color:ivory;
}
#canvas {
border:10px solid red;
background-color:black;
}
 </style>
</head>
<body>
<canvas id="canvas" width="400" height="300">
</canvas>
<script src="http://code.jquery.com/jquery-latest.min.js"
        type="text/javascript"></script>

<script type="text/javascript">
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
var $canvas = $("#canvas");
var canvasOffset = $canvas.offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var scrollX = $canvas.scrollLeft();
var scrollY = $canvas.scrollTop();

var isDown = false;
var startX;
var startY;

var toggle=0;
    var x=150;
    var y=100;
    var w=100;
    var h=100;
    var wasInside=false;

ctx.fillStyle = "#04B45F";
ctx.fillRect(x, y, w, h);

function changeColor() {
if (toggle == 0) {
    ctx.fillStyle = "#FFFFFF";
    toggle = 1;
} else {
    ctx.fillStyle = "#04B45F";
    toggle = 0;
}
ctx.fillRect(x, y, w, h);
}
function handleMouseMove(e) {

e.preventDefault();
var mx = parseInt(e.clientX - offsetX);
var my = parseInt(e.clientY - offsetY);

var isInsideNow = (mx > x && mx < x + w && my > y && my <= y + h);

if (isInsideNow && !wasInside) {
    changeColor();
    wasInside = true;
} else if (!isInsideNow && wasInside) {
    wasInside = false;
}

}

$("#canvas").mousemove(function (e) {
handleMouseMove(e);
});

</script>
</body>
</html>

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