设置源时不调用图像加载 [英] Image onload not called when setting source

问题描述

为什么在以下代码段中从未触发 onload 事件?

Why is the onload event never fired in following snippet?

var img = new Image()
img.onload = function() {
  alert("ok");
}
var svg = '<svg height="100" width="100"><circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" /></svg>'

img.src = 'data:image/svg+xml;base64,'+ btoa(svg);

jsfiddle 链接:https://jsfiddle.net/venmmn3b/1/>

Link to jsfiddle: https://jsfiddle.net/venmmn3b/1/

推荐答案

因为不行 -

• svg 字符串中缺少引号
• 图像触发错误而不是加载处理程序

var img = new Image()
img.onload = function() {
  console.log("ok");
}
img.onerror = function(e) {
  console.log("Not ok",e);
}
var svg = '<svg></svg>';
img.src = 'data:image/svg+xml;base64,'+ btoa(svg);

我什至尝试添加有效的 svg:

I even tried to add valid svg:

var img = new Image()
img.onload = function() {
  console.log("ok");
}
img.onerror = function(e) {
  console.log("Not ok",e);
}
img.src = 'data:image/svg+xml;utf8,<svg><text font-size="68" font-weight="bold" font-family="DejaVu Sans" y="52" x="4" transform="scale(.8,1.7)"><tspan fill="#248">W3</tspan>C</text> <path fill="none" stroke="#490" stroke-width="12" d="m138 66 20 20 30-74"/></svg>';

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