如何在JavaScript中将UTF8字符编码为Base64

Question

I tried like this when handling chinese, but the output is messy code garbled:

var a = "你好";
undefined
a
"你好"
a = unescape(encodeURIComponent(a));
"ä½ å¥½"
a
"ä½ å¥½"

compared to handling English:

var a = "Hello";
undefined
a
"Hello"
a = unescape(encodeURIComponent(a));
"Hello"

Here is my whole code:

var content = $("div#test").html();
content = unescape(encodeURIComponent( content ));
content = window.btoa(content);
content = "data:image/svg+xml;filename:{{ request.session.access_token.uid }}.svg;base64," + content;

UPDATED:

What I am trying to do is encoding a generated SVG as data url for user to download. I solved this problem by converting SVG to canvas (using CanVG) first and use html2canvas to generate base64 ... finally it works ...

Answer 1

Try roundtripping this, and it works fine:

decodeURIComponent(escape(window.atob(window.btoa(unescape(encodeURIComponent("‌​東京"))))))

Whether or not some intermediate result appears to be garbled is not relevant.

The problem with the window.btoa(decodeURIComponent(escape(unescape(encodeURIComponent("東京"))))) in one of the comments is the calls are not balanced and not in the right order.