Question

Is there a way to have javascript make an array of all the internal href=#’s on a page?

The idea is to have a drop down menu that would contain links to all anchors on a page.

Answer 1

Depending on the browser support you need, you can do this:

var elems = document.getElementsByTagName( 'a' );

var hashes = Array.prototype.map.call( elems, function( v, i ) {
    return v.hash;
}).filter( function( v, i, a ) { return !!v && a.indexOf( v ) === i; });

You can gain support for older browsers using the shims provided by MDN.

• map()^[docs]
• filter()^[docs]
• indexOf()^[docs]

---

In your comment, you noted that you want the name instead of the href.

You can do this, and it brings greater browser support automatically, though you’ll still want to get support for indexOf().

var elems = document.getElementsByTagName( 'a' );

var names = [];

for( var i = 0, len = elems.length; i < len; i++ ) {
    if( elems[i].name && names.indexOf( elems[i].name ) === -1 ) {
        names.push( elems[i].name ); 
    }
}