how can the value of an href attribute be changed using javascript/css?

Question

Assuming that the html contains the following structure:

    text


         


        

Answer 1

Put an id on it, e.g.

...
   ^^^^^^^^^^^^^^

then the JS is simply

document.getElementById('the_a_tag').href = 'new address goes here';

as long as you put the javascript AFTER the relevant HTML.

And note: CSS is for presentation only. With a few exceptions, it cannot affect the content of document elements, merely how they appear (color/size/position/etc...).