如何在包含特定文件扩展名的超链接中添加类？

Question

Can someone tell me how to take a string and run a function against it to check for a specific type of file (say a ".pdf"). If the string contains the file, then it needs to apply a "pdf" class to the anchor that contains the link.

Here's an example of a string:

<a href="/downloads/myfile.pdf">My PDF</a>

I would like it to be changed to this:

<a href="/downloads/myfile.pdf" class="pdf">My PDF</a>

Answer 1

Do this in CSS:

a[href$=".pdf"] {
   /* some rules */
}

But this may not be supported by some browser.

Alternatively, do this in Javascript, with jQuery or any library:

$('a[href$=".pdf"]').addClass('pdf'); // in jQuery

Or without library:

var elems = document.getElementByTagName('a');
for (var i = 0; i  < elems.length; ++i) {
    var a = elems[i];
    if (/\.pdf$/.test(a.href)) {
        a.className = 'pdf';
    }
}