JavaScript - Javascript Void Proper

I read somewhere (I think from Douglas Crockford) that void is a completely useless operator. What is its actual purpose? Is there anything it's good for?

I see lots of javascript:void(0) hyperlinks all over the place. From what I gather, it just disables the link's default behavior...buy why not just make the href="#" or return false from an onClick handler?

Can anyone enlighten me?

Hi,
So firstly this is likely not in the right place at all, as it's a bit OT but I figured it's the best place to ask..

I have to document 4 different tests to my code; what structure should I take when doing this?

I was thinking:
* State the aim of the test
* State the inputs, and what I believe the output should be.
* State the actual output, and whether this positively or negatively affect my code.

OK, I'm filling in for a coworker on a radio stations website.

The station currently streams live online. I want to add an event tracking so I can track how many people are streaming. I'm really new to js, but I think I figured it out (keyword is "think"). However, there was already an onclick event within the anchor tag. Can I have two in the same tag? Is there a better way to do this?

Code:

<a href="/fmstream/listen.asx" onclick="window.open(this.href,'Listen','resizable=no,location=no,menubar=no,scrollbars=no,status=no,toolbar=no,fullscreen=no,dependent=no,width=400,height=400,status'); return false" onClick="pageTracker._trackEvent('Stream','Listen_Button','Stream_Live');">
<img src="/images/filecabinet/folder1/listen1.png" alt="listen1"></a>

Hi all,

I have some code that attempts to save a user's preference settings. It first tries to use "localStorage", and if that fails (only old versions of MSIE), then a cookie is used instead.

I tried several different tests, such as:

Code:

    if (localStorage) {
        alert('True');
    } else {
        alert('False');
    }

and.......

if (typeof localStorage)....

and.......

if (typeof localStorage == 'object')....

but none of these are reliable. For example, if I intentionally misspell "localStorage" by instead using "localStor" (simulating a browser that doesn't understand the object name), the code simply does not run.

What I ultimately want is this:

Code:

if (user_wants_to_save_settings && localStorage) {
    save_to_local_storage;
} else
if (user_wants_to_save_settings) {
    save_to_cookie;
}

...unfortunately, that doesn't work. Anyone have ideas? I've been staring at this too long and am probably missing the obvious....

Thanks!

-- Roger

Is it just considered proper format to always have comment tags in javascript code
such as


*/ and /*

and //

etc?
thanks

Hello! I am trying to find a script that allows you to open multiple browser tabs and then close each of those tabs, either one by one or all at once.

Does anyone know how to do this please?

Thanks so much for your help.

I want to have another go at Javascript. I have several books on the subject but I find that my eyesight is a major problem. Therefore I want to try an on-line solution, preferably free.

I have Googled, but there are so many that I am almost dizzy with the choices.

Perhaps someone could recommend one. Not too fussy visually. My knowledge is VERY basic.

Frank

Does anyone know how to make URL links that use Javascript still work when
users have Javascript disabled on their browser?

The only reason I'm using JS on a URL is because my link opens a PDF file, and I'm forcing it not to cache so users have the latest version.

I tried the <script><noscript> tags, but I'm not sure if I'm using it
correctly, as my URL completely disappears.

Below is my HTML/Javascript code:

<p class="download">
<script type="text/javascript">document.write("<span
style=\"text-decoration: underline;\"><a href=\"javascript:void(0);\"
onclick=\"window.open(
'http://www.webchild.com.au/mediakit/Direct_Media_Kit_Web.pdf?nocache='+
Math.floor( Math.random()*11 ) );\" >The Child Magazines Media
Kit</a></span> (PDF 1 MB) ");</script>
<noscript><span style="text-decoration: underline;"><a
href="http://www.webchild.com.au/mediakit/Direct_Media_Kit_Web.pdf"
>The Child Magazines Media Kit</a></span> (PDF 1 MB)</noscript>
</p>


Thanks for any help,
Michael

Hi,

I have the following code snippet:
test.html
======
<script language="javascript" type="text/javascript">
var testVariable = "test";
</script>
<script language="javascript" type="text/javascript" src="test.js">
</script>

test.js
=====
var testVariable = window.top.testVariable;

In firefox, I'm able to access testvariable defined within test.html in test.js.

But in chrome, test.js couldnot get the window.top.testVariable field defined in test.html.

Can any one please let me know how i can make it work in chrome?. Am i missing something here?.

Hi Guys,
I am new at JavaScript and start to do some tutorials.What I am trying to do here is prompting user to input a name and if the name was valid the page(document) will display with all objects like the button.But if user enter a wrong name then the button will be disabled!
I create the following code but it did not work

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>New Web Project</title>
<script language="JavaScript" type="">
function changeColor(){
document.bgColor = "Gray";
}
</script>
</head>
<body>
<script language="JavaScript" type="text/javascript">
var person = "";
person = prompt('What is Your Name:');
if (person == "Foo") {
document.write("<h1 />Welcome " + person);
document.bgColor = "Yellow";
}
else {
document.write("<h1 />Access Denied!!!!");
document.bgColor = "Red";
document.getElementById("gree").disabled = true;
}
</script>

<div>
<p/><input id="gree" type="button" value="Gray " onClick="changeColor();">
</div>
</body>
</html>

as you can see I used the:
document.getElementById("gree").disabled = true;
but it did not work , could you please give an idea how I can solve this problem?
Thanks

I want to insert this js snippet
Code:

function addText(smiley) {
    document.getElementById('message').value += " " + smiley + " ";
    document.getElementById('message').focus();
    return false;
}

to a loaded iframe with name&id chtifrm. I can access it & change embed something in its html via using something like:

Code:

 $(parent.chtifrm.document.body).append('<div id=\"smly\" style=\"cursor:pointer;float:left;top:200px;display:none;position:absolute;\"><\/div>');

....
Code:

parent.chtifrm.document.getElementById('chatbox_option_disco').style.display == 'none'

but how do I insert js in the head of loaded iframe?

I got an index.php
Code:

<html>

<form action="bacakomik.php" method='post'>
<select name="kodekomik">
<option value='../komik1/|23'>Judul Komik1</option>
<option value="../komik2/|20">Judul Komik2</option>
<option value="../komik3/|10">Juduk Komik3</option>
<option value="../komik4/|20">Judul Komik4</option>
</select>
<input type="submit" />
</form>
<?php
echo ('<select>');
echo ('<option value= "'.$i.'">'.'Page '.$i.'</option>');
echo ('</select>');
?>
</html>

As you can see, each of the option brings specific value "../komik1/|23"
komik1 is a directory
| is a delimiter
23 is the pages in one chapter and can be considered also as how many images are there on a specific directory

This is my bacakomik.php
Code:

<?php
$dirkomik = $_POST['kodekomik'];
$exploded = explode("|", $dirkomik);
echo ($exploded[0]); //picture directory
echo ("<br>");
echo ($exploded[1]); //total page in the comic
$pagecount = (int)$exploded[1];
//Take last posted value, process it right away
echo ('<FORM name="guideform"> ');
echo ('<select name="guidelinks">');
$i=1;
do  {
echo ('<option value= "'.$i.'">'.'Page '.$i.'</option>');
$i= $i+1;
}while($i <= $pagecount); //Printing option and select
echo ("</select>");
?>
<input type="button" name="go" value="Go!" onClick="document.getElementById('im').src=document.guideform.guidelinks.options[document.guideform.guidelinks.selectedIndex].value+'.png';"> </FORM>
<img src="img0.jpg" id="im">

With the current code on bacakomik.php, I only can change the img src of id "im" in the same directory only. What I want is that the Javascript could "add" the "$exploded[0]" variable so that the picture can be loaded from different directory. Anyone can do this?
I believe that the fix should be somewhere on input tag inside OnClick, or do you know where?

Anyway, I found this on the net
http://p2p.wrox.com/php-faqs/11606-q...avascript.html
Please help me to those who can...

Hi Guys I am trying to modify the functionality of my page. I want to be able to activate this piece of code using another javascript function.

This is the code I want to activate:

Code:

<script type="text/javascript"><!--
$('#button-cart').bind('click', function() {
	$.ajax({
		url: 'index.php?route=checkout/cart/update',
		type: 'post',
		data: $('.product-info input[type=\'text\'], .product-info input[type=\'hidden\'], .product-info input[type=\'radio\']:checked, .product-info input[type=\'checkbox\']:checked, .product-info select, .product-info textarea, .date_data input[type=\'text\']'),
		dataType: 'json',
		success: function(json) {
			$('.success, .warning, .attention, information, .error').remove();
			
			if (json['error']) {
				if (json['error']['warning']) {
					$('#notification').html('<div class="warning" style="display: none;">' + json['error']['warning'] + '<img src="catalog/view/theme/default/image/close.png" alt="" class="close" /></div>');
				
					$('.warning').fadeIn('slow');
				}
				
				for (i in json['error']) {
					$('#option-' + i).after('<span class="error">' + json['error'][i] + '</span>');
				}
			}	 
						
			if (json['success']) {
				$('#notification').html('<div class="success" style="display: none;">' + json['success'] + '<img src="catalog/view/theme/default/image/close.png" alt="" class="close" /></div>');
					
				$('.success').fadeIn('slow');
					
				$('#cart_total').html(json['total']);
				
				$('html, body').animate({ scrollTop: 0 }, 'slow'); 
			}	
		}
	});
});
//--></script>

And this is how I want the format of the function to be:

function testsession() {
if there is a session called 'hiredate' {
activate the script above
}
else {
var el = document.getElementById("product_data");
}
}


I just dont know how to write this in javascript

Could you help me if possible please

Hey,
I've got to make the values of some textboxes change the co-ordinates of my sprite on a canvas and havent a clue on how to do it,

Here is my form with the two textboxes and submit button:
<form>
x: <input type="text" name="x" /><br />
y: <input type="text" name:"y" /><br />
<input type="submit" value="Submit"/><br />
</form>

And i need it so that they change the values of these:

//this shows where my sprite will start on the canvas
var block_x;
var block_y;
searched the internet for hours and cant really find anything i understand or works.
any help is much appreciated

All --

I have a JavaScript config file called gameSetting.js which contains a bunch of variables which configures a particular game.

I also have a shared JavaScript library which uses the variables in gameSetting.js, which I include like so:

<script type="text/javascript" src="gameSetting.js" ></script>
<script type="text/javascript" src="gameLibrary.js" ></script>

In gameSetting.js I have:

$(document).ready(function()
{
// call some functions / classes in gameLibrary.js
}

in Firefox, Safari, and Chrome, this works fine. However, in IE, when it's parsing gameSetting.js, it complains that the functions that live in gameLibrary.js aren't defined. When it gets to parsing gameLibrary.js, the variables in gameSetting.js are reported as not being defined.

I've tried dynamically bootstrapping the gameLibrary file using this function in document.ready for dynamic load...

$.getScript("gameLibrary.js");

However, the same problem still happens in IE, where when it parses the files individually it's not taking into context the file/variables that came before, so it's not an out of load order problem.

My options a

1) collapsing all the functions in gameLibrary.js and variables in gameSetting.js into one file. However, this is not practical because this is dealing with literally hundreds of games, and having a gameLibrary.js in ONE location for ONE update is what makes most logical sense.

2) figure out a way to get this to work where variables in file1 are accessible to file2 in IE (as it seems they are in other browsers).

jQuery seems to be able to have multiple plugins that all refer to the based jQuery-1.3.2.js, so I know there is a way to get this to work.

Help appreciated.

Nero