Having trouble using jQuery to set meta tag values

Question

I'm trying to set meta tags using jQuery (please don't reply that this doesn't make sense since search engines blah-blah-blah... I am loading invoking 3rd party Javascript functions that examine these vales, such as Tweetmeme and Facebook).

If I use:

 $('meta[name=some-name]').attr('content', 'some value');

it does work to set the value of an existing meta tag, but does not create a meta tag if such a named one does not exist.

If you have insight or experience with this, please reply...

Answer 1

You can do this, not the cleanest, but what you're trying to do is pretty odd so there's not a great way to handle it:

var mt = $('meta[name=some-name]');
mt = mt.length ? mt : $('<meta name="some-name" />').appendTo('head');
mt.attr('content', 'some value');

The conditional expression in there checks .length, which is 0 or false if not found, if that's the case we create the element and append it to the head, whether it was added or originally found, mt is set to the <meta> with that name now, and you can set the attribute.

Answer 2

Leveraging Nick's code, I made a function to do the meta tag setting, creating if necessary. Should this be of use to anyone...

    function setOrCreateMetaTag(metaName, name, value) {
        var t = 'meta['+metaName+'='+name+']';
        var mt = $(t);
        if (mt.length === 0) {
            t = '<meta '+metaName+'="'+name+'" />';
            mt = $(t).appendTo('head');
        }
        mt.attr('content', value);
    }

The metaName most often might be assumed to be "name" but I am also having to set "property" as well, so made the function handle a meta meta-name.