Firebug : web development evolved

I found firebug very useful while developing my Paint Chat (which is not a big code as such but still), so here it goes in admiration of firebug:

Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.

Firebug is firefox addon that helps you in webdevelopment with
its powerful feature such as javascript debugger, Inspect and edit HTML, Tweak CSS to perfection, Monitor network activity, Explore the DOM and many more. Feature I like most is its quickly diagnosing problem, it allows you set break points and checking intermediate values of variable for javascript thus making a great javascript debugger. Many times you are stuck at where did the code went wrong so in way its a lot useful in saving time.

I also like is its inspecting html and modifying html and css on fly and see the results with helpful tooltips. It also help in positioning of divs, images with its nice feature of visuallizing css metrics with ruler and box model coloring(HTML inspecting).

It other great feature is its interface which is comes with browser window split in two halves one for your website and one is extension interface (though it also can be detached from it). I am also a fan of Web developer toolbar extension but what it lacks is a java debugger and this great interface but both are a must of a web developer.

If you want to develop firefox extension..

February 12, 2007 | Filed Under programming, tips, web2.0, webdev | 1 Comment

Play with html using javascript

Javascipt can be very fruitful and flexible when it comes to modifying webapges dynamically (though client side). Javascript can be helpful in creating response to browser events like mouseup, mouseover etc, veryfying of form values prior to submitting them, changing style and value of html elements dynamically.
Examples i disscuss here are being user by me in developing Paint Chat !! So here I go..
You can write javascript functions and code in section as:

<script type="text/javascript">function test(){alert("test javascript");}</script>

Action on events:

Example of events can be mouseclick, keystroke, submitting form etc.
With onload()

 <body onload="init()">

Now init() function will be called when this html page is being loaded.
For links, javascript function can be evoked when clicking, mouseover over links like

 <a href="javascript:replay()" mce_href="javascript:replay()">Refresh ! </a>

Now function replay() will be called when Refresh! is clicked. For input text box

<input type="text" size="30" id="search" onchange="suggest()">;

Now whenever content of textbox changes the function suggest() will be called. It can be useful when feature like google suggest has to be implemented or so.

On submitting forms:

<form method="post" action="some.php" onsubmit="return checkForm()">

So whenever this form is being submitted checkForm() function will be called and can be helpful in verifying values of form elements.

onMouseOver and onMouseOut:

<a href="http://www.aburad.com/blog" mce_href="http://www.aburad.com/blog" onmouseover="fade()"><img src="image.gif" mce_src="image.gif"> </a>

Now when mouse is over image fade() function will be called and can be used for animate and styling purposes.

Registering of events

A simple way can be:
Conside the html code : <div id="sample"> ..... some... html..text.. </div>
Now using javascript you can register event for this div by:

 var div_sample = document.getElementById('sample');div_sample.onmousedown=sampleMouseDown ;

Now whenever mouseover ocours over this div html element sampleMouseDown() function will be called. Events can also be registered using addEventListener() . Find more information baout it here:Advanced event registration models

Modify Style and values for html elements

Within some javascript function, you can first get the element object by getElementByID() getElementsByName() for example conside the javascript code:

document.getElementById("colorcode").innerHTML = "#000000"; document.getElementById("bgtest").style.backgroundColor= "green";

The first line find the html element with id colorcode and then set its value to “#000000″ using innerHTML. In second line, it sets the background of html element with id “bgtest” to green.

Some other tweaks which were useful :

Calling some function repeatedly with some time interval, consider javascript code:

var intervalID = setInterval(drawCurve, 100);

So the drawCurve() function will be called repeatedly after 100ms. You can cancel this process( removing repeatedly calling) by clearInterval(intervalID);