Javascript 可以从 Canvas 构造函数创建 HTML5 Canvas 元素吗
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can the HTML5 Canvas element be created from the Canvas constructor
提问by Overfloater
I would like to be able to make Canvas elements from the constructor so that I could make a function like this.
我希望能够从构造函数制作 Canvas 元素，以便我可以制作这样的函数。
function createCanvasContext(height,width)
{
var body = document.getElementsById('body')[0];
var canvas = new Canvas();
canvas.height=height;
canvas.width = width;
var context = canvas.getContext('2d');
body.appendChild(canvas);
return context;
}
I get an error at the line var canvas = new Canvas() saying that 'Canvas is undefined' does HTML5 not allow creating elements from the constructor? or are there parameters that I need to pass to the constructor. Any ideas would be great.
我在 var canvas = new Canvas() 行收到错误，说“Canvas 未定义”HTML5 是否不允许从构造函数创建元素？或者我需要传递给构造函数的参数。任何想法都会很棒。
回答by Simon Sarris
While you can do new Image()just fine, new Canvas()isn't a thing! CanvasIsn't even a thing, though HTMLCanvasElementis. Nonetheless you cannot use its constructor.
虽然你可以做得new Image()很好，但new Canvas()不是一回事！Canvas甚至不是一件事，虽然HTMLCanvasElement是。尽管如此，你不能使用它的构造函数。
document.createElement('canvas');is what you want. You have to use that, just like with divs.
document.createElement('canvas');是你想要的。你必须使用它，就像使用 div 一样。
回答by yapingchen
var mycanvas = document.createElement("canvas");
mycanvas.id = "mycanvas";
document.body.appendChild(mycanvas);
