Curiouser and Curiouser!

Curiouser and Curiouser! on javascript http://matt.blogs.it/ RSS feed for topic javascript Copyright 2006 Matt Mower Squib/0.1 self@mattmower.com self@mattmower.com en-gb No messing with JavaScript Tue, 19 Aug 2003 20:16:51 +0100 For anyone doing Javascript work I can highly recommend both David Flanagan's <A href="http://www.amazon.co.uk/exec/obidos/ASIN/0596000480/ref=sr_aps_books_1_1/026-3773900-4657257">JavaScript: The Definitive Guide</A> and Danny Goodman's <A href="http://www.amazon.co.uk/exec/obidos/ASIN/0596004672/ref=sr_aps_books_1_1/026-3773900-4657257">JavaScript & DHTML Cookbook</A>.  The guide is a pretty comprehensive reference that I turn to a lot.  The cookbook is a very interesting mix of practical JavaScript and DHTML techniques.  I'm particularly interested in the possibilities for drag & drop in web interfaces.  Marc Barrot uses this to good effect in <A href="http://demo.weboutliner.com/webOutliner/">WebOutliner</A>. http://matt.blogs.it/entries/00001562.html Hooking Javascript event handlers Tue, 28 Oct 2003 22:12:42 +0000 Working on the K-Collector client for MovableType I have the need to add an onload handler to a page and onsubmit handler to a form.  In this case I have no control over whether there may already be handlers and I certainly don't want to interfere with them if they exist.  I couldn't see an obviously supported way of doing this and came up with the following Javascript function which seems to do the trick. <div style="margin-left: 40px;">function registerHandler( objectRef, handlerProperty, handlerCode ) {     var currentHandler = objectRef[handlerProperty];     objectRef[handlerProperty] =         function() {             if( currentHandler ) {                 currentHandler();             }             return eval( handlerCode );         }; } </div> This can be invoked from within a <script> section at the appropriate point in a document, for example: <div style="margin-left: 40px;">registerHandler( window, "onload", "alert( 'page has loaded' )" ); </div> or <div style="margin-left: 40px;">registerHandler( document.forms.test, "onsubmit", "alert( 'you cannot submit this form' ); false;" ); </div> The caveat to this approach is demonstrated in the second example.  By default you would return false in a handler where you wanted to prevent the default behaviour.  However return is only valid within the context of a function so you cannot use it in an eval().  However eval itself returns the last expression so making that false amounts to the same thing. http://matt.blogs.it/entries/00001688.html Toggling checkboxes in the Radio news aggregator Tue, 17 Feb 2004 20:51:29 +0000 A while back I wrote a modification to the Radio news aggregator page which added a button for toggling all the checkboxes on or off. This was pretty handy but trashed by a Userland update. I could never muster the willpower to figure out how I did it again, and watch it disappear again at some unspecified point in the future so i've done without. Today I slapped myself for being a fool and wrote a JavaScript <a href="javascript:(function(){var inputs=document.getElementsByTagName('input');for(var i=0;i<inputs.length;i++){if(inputs[i].type=='checkbox'){inputs[i].checked=!inputs[i].checked;}}})()">bookmarket</a> which does the same thing. It just toggles every checkbox it finds on the page. I've learned some more <a href="http://subsimple.com/bookmarklets/tips.asp#Encapsulation">tricks</a> for writing Bookmarklets, since last time, so this one should work the same on IE and Mozilla (although I won't be testing it on IE). http://matt.blogs.it/entries/00001901.html Javascript for open in new tab Fri, 06 Aug 2004 20:23:35 +0100 Does anyone know a way to have Javascript code open a link in a new Mozilla tab?  What I want to be able to do is automatically add a "handle" to every link on the page which, when you click it, opens the link in a tab. http://matt.blogs.it/entries/00002429.html The experts have it Fri, 06 Aug 2004 21:07:13 +0100 For £6 I signed up to <a href="http://www.experts-exchange.com/">Experts Exchange</a> for a month since they were the only site that appeared to have an answer for my question about opening tabs via Javascript.  I had a sneaking suspicion I knew what I was buying and, indeed, the <a href="http://bugzilla.mozilla.org/show_bug.cgi?id=105409">answer</a> is in the negative.  Oh well.  EE looks like a good resource and I have a month to ask more questions. An interesting side note: Most of the reasoning given for why programmatic tab control is "a bad thing" was about user choice and, yet, I am a user and I want this choice which has been denied me. http://matt.blogs.it/entries/00002432.html Them nifty boxes Tue, 10 May 2005 22:16:53 +0100 <a href="http://farm.tucows.com/blog/_archives/2005/5/10/670308.html">Docking boxes</a> look pretty cool. <a href="http://brothercake.com/scripts/dbx/dbx.html?PHPSESSID=2430f08da9b77b338dbd6f38f468d043">Check</a> <a href="http://brothercake.com/scripts/dbx/dbx-news.html?PHPSESSID=2430f08da9b77b338dbd6f38f468d043">out</a> <a href="http://brothercake.com/scripts/dbx/dbx-buttons.html?PHPSESSID=2430f08da9b77b338dbd6f38f468d043">the</a> <a href="http://brothercake.com/scripts/dbx/dbx-cute.html?PHPSESSID=2430f08da9b77b338dbd6f38f468d043">demos</a>. http://matt.blogs.it/entries/00002572.html Getting your logging fix JS style Tue, 06 Sep 2005 10:40:16 +0100 <a href="http://www.alistapart.com:80/articles/jslogging">Javascript logging</a> looks handy. http://matt.blogs.it/entries/00002883.html