Add a bookmark that is only javascript, not a URL

I'm thinking that the reason I can't do this is because it might be a huge security hole, but here goes...

I want to have a bookmark on my browser (FF3, preferably) that is only a snippet of javascript code. It would merely construct a URL based on the current date and then do a window.location = on that URL.

I know that I could make a page and keep it on my local machine and just refer to it that way, but I was just wondering if you could bypass that step and actually have the "location" of the bookmark really just be javascript. I could have sworn that this was possible years ago, but I can't find anything that tells me either way now.

What you want is a http://en.wikipedia.org/wiki/Bookmarklet">bookmarklet</a> they are easy to create and should work in most major browsers.

Edit: Stack overflow seems not to allow creating bookmarklets in the context of the site, basically you can create a new bookmark and type the following in the location field

javascript:window.location='http://www.google.com/search?q='+Date()</pre>

to get a bookmarklet that searches google for the current date.

It is worthy of note that you can put that in a function wrapper as well. imranamajeed nicely illustrated that for us... but apparently I'm too new to the site to up his post. :P

so for clarity:

javascript:(function(){
  location.href = location.href + "#";
})();

(the carriage returns did not affect performance in chrome and IE)

One minor catch. IE can only handle a 508 character URL in this format. If you save it in IE with a url longer than this, it will truncate without warning and thus fail.

If you need a really complex script, you'll need to use a "hosted" bookmarklet, where you have a short bookmark that injects a script tag into the page, to "call" your hosted bookmarklet.

It isn't as nice/portable, but its the only workaround.

Google Bookmark

javascript:(function(){var%20a=window,b=document,c=encodeURIComponent,d=a.open("http://www.google.com/bookmarks/mark?op=edit&output=popup&bkmk="+c(b.location)+"&title="+c(b.title),"bkmk_popup","left="+((a.screenX||a.screenLeft)+10)+",top="+((a.screenY||a.screenTop)+10)+",height=420px,width=550px,resizable=1,alwaysRaised=1");a.setTimeout(function(){d.focus()},300)})();

Well, I just created a bookmark in FF3, went back and updated it and added the following test:

javascript:alert('Wacky%20test%20yo');

Low and behold, after I saved and loaded, I was able to get my alert.

I'm sure you can work up something similar for your needs.