Question

Html entities must be encoded in alt attribute of an image in HTML page. So

<img id="formula" alt="A &rarr; B" src="formula.png" />

will work well.

On the other hand, the same JavaScript code will not work

document.getElementById('formula').alt = 'A → B';

and will produce A → B instead of A → B.

How to do it through JavaScript, when it is not possible to put the special (unencoded) characters in the source code?

Answer 1

Here’s an alternative if you can’t save your file using a Unicode format:

function decodeHTML(str) {
    return str.replace(/&#(\d+);?/g, function() {
        return String.fromCharCode(arguments[1])
    });
}

However, this requires you to use the numeric representation. In this case →.