canvas.getContext（'2d'）在html页面中工作正常。但不能在asp.net中工作 [英] canvas.getContext('2d') works fine in html page.but not with asp.net

问题描述

I am developing a html5 image viewer in asp.net.am testing the script with .html page it was working fine.when using the script in .aspx page it throws me the following error


error:0x800a01b6 - Microsoft JScript runtime error: Object doesn't support property or method 'getContext'

the bold line throws the above error

<script>
        function loadImages(sources, callback) {
            var images = {};
            var loadedImages = 0;
            var numImages = 0;
            // get num of sources
            for (var src in sources) {
                numImages++;
            }
            for (var src in sources) {
                images[src] = new Image();
                images[src].onload = function () {
                    if (++loadedImages >= numImages) {
                        callback(images);
                    }
                };
                images[src].src = sources[src];
            }
        }
        var canvas = document.getElementById('myCanvas');
        var context = canvas.getContext('2d');

        var sources = {
            web1: 'http://localhost:2861/images/1.jpg',
            web2: 'http://localhost:2861/images/2.jpg'
        };

        loadImages(sources, function (images) {
            context.drawImage(images.web1, 100, 35, 256, 256);
            context.drawImage(images.web2, 350, 55, 93, 104);
        });

   </script>

推荐答案

您是否看过Chrome中的对象，看看它是什么以及它有哪些方法？如果你为两个页面都这样做，并且对象类型是相同的，那么我唯一能想到的是DTD是否以某种方式改变了页面的性质和它上面的对象。



如果您将HTML逐字粘贴到ASPX中，它是否仍然会出错？

Have you looked at the object in Chrome to see what it IS and what methods it has ? If you do that for both pages, and the object types are the same, then the only other thing I can think of is if the DTD is somehow changing the nature of your page and the objects on it.

If you paste your HTML verbatim in to an ASPX, does it still give the error ?

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