- Its extremely handy for short and snappy stuff
- Everything under the sun is available in CPAN but figuring out which is best suited for your needs is a bitch
- While developing webapps with CGI not knowing
use Carp::qw(fatalsToBrowser);is the last thing you want to do (coz I did that) - Why ? Oh why do warnings and
use strict;exist if you can write stuff faster without it :((
Sunday, January 08, 2006
PERL update
After almost 4 months of PERL this is what I have to say.
addEvent()
A lots been said and done here. Here's my take if attachEvent does not give you access to the "this" pointer don't use it, instead use the age old method supported by most browsers :)
<html>
<head>
<title>Javascript Test Page</title>
<script type="text/javascript">
/*****************************************************************************
* Helper Functions
*****************************************************************************/
var onlyUnique = true; // default
function registerListener(target, event, listener) {
if ( target[event + "Count"] ) {
target[event + "Count"] = parseInt(target[event + "Count"]) + 1;
} else {
// first handler so add default event handler
target[event + "Count"] = 1;
target.defaultHandler = defaultHandler;
target["on" + event] = function(evt) {
evt = window.event ? window.event : evt;
target.defaultHandler(event, evt);
};
}
var currCount = parseInt(target[event + "Count"]) - 1;
if ( onlyUnique ) {
for ( var i = 0; i < currCount; i++ ) {
if ( target[event + i] == listener ) {
target[event + "Count"] = currCount;
return false;
}
} // endfor i
} // endif onlyUnique
target[event + currCount] = listener;
return true;
}
function unRegisterListener(target, event, listener) {
if ( target[event + "Count"] ) {
var currCount = parseInt(target[event + "Count"]);
for ( var i = 0; i < currCount; i++ ) {
if ( target[event + i] == listener ) {
target[event + i] = null;
currCount--; // removed one
break;
}
} // endfor i
for ( var j = i; j < currCount; j++ ) {
target[event + j] = target[event + (j + 1)];
} // endfor j
if ( currCount < 1 ) {
// cleanup default event handler
target["on" + event] = null;
}
target[event + "Count"] = currCount;
}
}
function defaultHandler(eventName, evt) {
if ( this[eventName + "Count"] ) {
var currCount = parseInt(this[eventName + "Count"]);
for ( var i = 0; i < currCount; i++ ) {
this[eventName + i](evt);
} // endfor i
}
}
/*****************************************************************************
* Event Handler Functions
*****************************************************************************/
function addEvent(target, event, func) {
if ( target.addEventListener ) {
target.addEventListener(event, func, false);
} else {
registerListener(target, event, func)
}
}
function removeEvent(target, event, func) {
if ( target.removeEventListener ) {
target.removeEventListener(event, func, false);
} else {
unRegisterListener(target, event, func)
}
}
/*****************************************************************************/
function gel(idName) {
return document.getElementById ? document.getElementById(idName) : false;
}
addEvent(window, "load", one);
addEvent(window, "load", two);
addEvent(window, "load", initialize);
var oneCount = 0;
function one() {
var text = "[one][" + oneCount + "]" + this.id;
oneCount++;
var div = document.createElement("div");
div.appendChild(document.createTextNode(text));
gel("oneDiv").appendChild(div);
}
var twoCount = 0;
function two(evt) {
var text = "[two][" + twoCount + "]" + evt.type;
twoCount++;
var div = document.createElement("div");
div.appendChild(document.createTextNode(text));
gel("twoDiv").appendChild(div);
}
function initialize() {
alert("[initialize]");
alert("adding one");
add1();
alert("adding two");
add2();
alert("done");
addEvent(gel("remove1"), "click", remove1);
addEvent(gel("remove2"), "click", remove2);
addEvent(gel("add1"), "click", add1);
addEvent(gel("add2"), "click", add2);
}
function remove1() {
for ( var i = 0; i < 10; i++ ) {
remove(one);
}
alert(gel("anchor").clickCount + " handler(s) left");
}
function remove2() {
for ( var i = 0; i < 10; i++ ) {
remove(two);
}
alert(gel("anchor").clickCount + " handler(s) left");
}
function remove(which) {
removeEvent(gel("anchor"), "click", which);
}
function add1() {
for ( var i = 0; i < 10; i++ ) {
add(one);
}
alert(gel("anchor").clickCount + " handler(s) present");
}
function add2() {
for ( var i = 0; i < 10; i++ ) {
add(two);
}
alert(gel("anchor").clickCount + " handler(s) present");
}
function add(which) {
addEvent(gel("anchor"), "click", which);
}
</script>
</head>
<body>
<a id="anchor" href="#">[Test]</a>
<a id="remove1" href="#">[Remove 1]</a>
<a id="remove2" href="#">[Remove 2]</a>
<a id="add1" href="#">[Add 1]</a>
<a id="add2" href="#">[Add 2]</a>
<div id="test"></div>
<table>
<tr>
<td valign="top">
<div id="oneDiv"></div>
</td>
<td valign="top">
<div id="twoDiv"></div>
</td>
</tr>
</table>
</body>
</html>
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