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<h1 id="6601">Developer Notes for prototype.js</h1>

This guide is based on the <a href="http://www.sergiopereira.com/articles/prototype.js.html">

Developer Notes for prototype.js</a> by Sergio Pereira.

<h2 id="6603">What is that?</h2>

<p id="830726" class="block-content">

In case you haven't already used it, <a href="http://prototype.conio.net">prototype.js</a> is a

    JavaScript library written by <a href="http://www.conio.net">Sam Stephenson</a>.

    This amazingly well thought and well written piece of <b>standards-compliant</b> code takes a lot of

    the burden associated with creating rich, highly interactive web pages that characterize the Web 2.0 off your back.

</p>

<p id="830727" class="block-content">

    If you tried to use this library recently, you probably noticed that documentation is not one

    of its strongest points. As many other developers before me, I got my head around prototype.js by

    reading the source code and experimenting with it. I thought it would be nice to take notes while

    I learned and share with everybody else.

</p>

<p id="830728" class="block-content">

    As you read the examples and the reference, developers familiar with the Ruby

    programming language will notice an intentional similarity between Ruby's

    built-in classes and many of the extensions implemented by this library.

</p>

<h2 id="6604">Using the <tt>$()</tt> function</h2>

<p id="830729" class="block-content">

    The <tt>$()</tt> function is a handy shortcut to the all-too-frequent <tt>document.getElementById()</tt> function

    of the DOM. Like the DOM function, this one returns the element that has the id passed as an argument.

</p>

<p id="830730" class="block-content">

    Unlike the DOM function, though, this one goes further. You can pass more than one id and

    <tt>$()</tt> will return an <tt>Array</tt> object with

    all the requested elements. The example below should illustrate this.

</p>

<com:TTextHighlighter Language="javascript" CssClass="source block-content" id="code_830252">

<com:TClientScript UsingClientScripts="prado" />

<div id="myDiv">

    <p id="830731" class="block-content">This is a paragraph</p>

</div>

<div id="myOtherDiv">

    <p id="830732" class="block-content">This is another paragraph</p>

</div>

<input type="button" value=Test1 onclick="test1();" />

<input type="button" value=Test2 onclick="test2();" />

<script type="text/javascript">

/*<![CDATA[*/

function test1()

{

    var d = $('myDiv');

    alert(d.innerHTML);

}

function test2()

{

    var divs = $('myDiv','myOtherDiv');

    for(i=0; i<divs.length; i++)

    {

        alert(divs[i].innerHTML);

    }

}

/*]]>*/

</script>

</com:TTextHighlighter>

<p id="830733" class="block-content">

    Another nice thing about this function is that you can pass either the <tt>id</tt> string or the element object itself,

    which makes this function very useful when creating other functions that can also take either form of argument.

</p>

<h2 id="6605">Using the <tt>$F()</tt> function</h2>

<p id="830734" class="block-content">

    The <tt>$F()</tt> function is a another welcome shortcut. It returns the value of any field input control,

    like text boxes or drop-down lists. The function can take as argument either the element <tt>id</tt> or the element object itself.

</p>

<com:TTextHighlighter Language="javascript" CssClass="source block-content" id="code_830253">

<input type="text" id="userName" value="Joe Doe" />

<input type="button" value=Test3 onclick="test3();" />

<script type="text/javascript">

/*<![CDATA[*/

function test3()

{

    alert($F('userName'));

}

/*]]>*/

</script>

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<div class="last-modified">$Id: Scripts1.page 1650 2007-01-24 06:55:32Z wei $</div></com:TContent>