Updating page with "document.write" removes formatting - javascript

I've been wondering if there is a way to prevent my functions hiding any current text/formatting.
<body>
<script type="text/javascript">
document.body.style.backgroundColor = "#F5F0EB";
var page = 0
function flip(){
document.write(page);
page++;
}
</script>
<input type=button value="Next" onClick="flip()">
</body>
When I press the button I lose the coloured background and the text appears. Is there a way to make the background stay and the text appear?

Yes, by not using document.write(). MDN explains it clearly:
Writing to a document that has already loaded without calling
document.open() will automatically perform a document.open call.
And about document.open() it says:
If a document exists in the target, this method clears it.
What you should be doing, is manipulate nodes in the DOM. For example, you could change the inner HTML of the body:
document.body.innerHTML += page;
Alternatively, you could create a text node and append it:
var textNode = document.createTextNode(page);
document.body.appendChild(textNode);
In both cases, the current document is not flushed, it is only modified.

This is happening because you're writing non-html to a document which should be html. As indicated by others, it may also be clearing your existing html. Instead of using document.write, you may want to append new elements to your document.
You can do that using the document.createElement function and document.appendChild function.
Here's what a quick Google search brought back:
http://www.dustindiaz.com/add-and-remove-html-elements-dynamically-with-javascript/

You are writing the page to document which is overwriting all over your HTML. Instead, write out the content to a DIV.
This should fix your background color problem as well.
Here is a JS Fiddle with an example.
<script type="text/javascript">
document.body.style.backgroundColor = "#F5F0EB";
var page = 0
function flip(){
document.getElementById("contentgoeshere").innerHTML=page;
page++;
}
</script>
<input type=button value="Next" onClick="flip()">
<div id="contentgoeshere">
</div>
Good luck.

As Mattias Buelens explained, document.write calls the open method, which clears the DOM, simply because -after loading- the document.close method is called automatically. There are a number of alternatives you can use, of course.
Use the innerHTML attribute of the body element, for example.
Using document.createElement and document.body.appendChild is an option, too
But perhaps it's worth taking into consideration that both methods have their downsides: using innerHTML allows you to inject badly formatted markup into the DOM, and could leave you vulnerable to XSS attacks.
Using document.createElement is slower (generally) and often requires more code, which in turn makes your script(s) less maintainable.
You could use something like this:
var flip = (function(tempDiv)
{//create a div once
var page = 0,
targetDiv = document.getElementById('contentgoeshere');//closure variables
//page is now no longer an evil global, and the target element into which
//we will inject new data is referenced, so we don't have to scan the DOM
//on each function call
return function(overridePage)//optional argument, just in case
{//actual flip function is returned here
overridePage = overridePage || page++;//new content
tempDiv.innerHTML = overridePage;//render in div that isn't part of the DOM
//any number of checks can go here, like:
if (tempDiv.getElementsByTagName('script').length > 0)
{
alert('Naughty client, trying to inject your own scripts to my site');
return;
}
targetDiv.innerHTML = tempDiv.innerHTML;
//or, depending on your needs:
targetDiv.innerHTML = tempDiv.innerText;//or the other way 'round
};
}(document.createElement('div')));
A couple of side-notes: as it now stands, this function won't work because the DOM has to be fully loaded for the closure to work. A quick fix would be this:
var flip;//undefined
window.onload = function()
{
flip = (function(tempDiv)
{
var page = 0,
targetDiv = document.getElementById('contentgoeshere');
return function(e)
{
tempDiv.innerHTML = e instanceof Event ? page++ : (e || page++);//ternary + logical or
//your [optional] checks here
targetDiv.innerHTML = tempDiv.innerHTML;
if (e instanceof Event)
{//this part is optional, but look it up if you want to: it's good stuff
e.returnValue = false;
e.cancelBubble = true;
if (e.preventDefault)
{
e.preventDefault();
e.stopPropagation();
}
}
return e;
};
}(document.createElement('div')));
//instead of using the HTML onclick attribute:
document.getElementById('buttonID').onclick = flip;//use as event handler
};
Note that window.onload causes memory leaks on IE<9, check this link for the solution to this issue

Related

How can i improve my personnal jQuery Dialog plugin

I've been coding my own dialog system for exercising and to be able to customize it as i want. Here is what i've done.
$(function(){
$.fn.window = function(attr){
var $self = this;
if(!attr)
attr = {};
$.extend({
autoOpen:false
}, attr);
/**
* Create the window by updating the current jQuery block
* And adding the required classes
*/
this.create= function(){
// Already created
if($self.hasClass('window-window'))
return;
$self.addClass('window-window');
// Creating the header and appending the title
var $windowHeader = $('<div class="window-header"></div>');
var $title = $self.attr('title');
$windowHeader.html($title);
$windowHeader.append('<div class="loading-item loading-item-footer round-loading25" ' +
'data-loading-item="window" style="display:none"></div>');
// Wrapping content in a window-content class
// So the window has the proper format
$self.children().wrapAll('<div class="window-content"></div>');
$self.prepend($windowHeader);
};
/**
* Open the window in a blackish div
* With the events to close it
*/
this.open = function(){
// Creating the background
var $backgroundDiv = $('<div></div>');
$backgroundDiv.addClass('window-background');
// Making it take the size of the page
$backgroundDiv.height($(window).height());
$backgroundDiv.width($(window).width());
$self.detach().appendTo($backgroundDiv);
// The window is hidden by default, showing it
$self.show();
$('html').prepend($backgroundDiv);
// Handling closing the window
$backgroundDiv.click(function(e){
var $target = $(e.target);
if(!$target.hasClass('window-background'))
return;
$self.hide();
$self.detach().appendTo('html');
$backgroundDiv.remove();
});
};
this.create();
if(attr.autoOpen){
this.open();
}
};
});
For now i have doubt about the fact that i'm putting the window out of his native block, in the end of the html document. I wish to put it back to his position but i have no idea yet how to do it. Any idea ?
First of all, you create a jQuery function, but you do it on document.ready $(...). You should just create it, otherwise the function will not be available for other code until document has loaded.
Then you want to insert the window in the same place as the original element, for that you have insertBefore and insertAfter in jQuery. You use prepend, but that inserts it as the first element of $self.
I would urge you to look at the method chaining of jQuery which may make your code much more readable. Instead of:
// Creating the background
var $backgroundDiv = $('<div></div>');
$backgroundDiv.addClass('window-background');
// Making it take the size of the page
$backgroundDiv.height($(window).height());
$backgroundDiv.width($(window).width());
use
// Creating the background
var $backgroundDiv = $('<div></div>')
.addClass('window-background')
// Making it take the size of the page
.css({
height:$(window).height(),
width:$(window).width()
});
for example.
You also use CSS classes to store information, like if something had been clicked or not. That may be OK, but consider that you may want change the CSS classes and suddenly the functionality of your code is strongly linked to the design. Maybe using .data() instead would be better, even if you add more code to also style your elements.
You use .wrap to take the original content and put it in the window. That may be what you wanted all along, but also take a look at https://api.jquery.com/clone/ which allows you to get the elements without removing them from their original source. Again, only if it works better for you.
As a last advice, use http://jsfiddle.net to share your working code, so other people may not only comment on it, but see it in action as well.

addEventListener to div element

I am trying to fire a script when the contents of a div are altered, specifically when a div receives the next set of results from a js loaded paginator.
I have this:
<script script type="text/javascript" language="javascript">
document.addEventListener("DOMCharacterDataModified", ssdOnloadEvents, false);
function ssdOnloadEvents (evt) {
var jsInitChecktimer = setInterval (checkForJS_Finish, 111);
function checkForJS_Finish () {
if ( document.querySelector ("#tester")
) {
clearInterval (jsInitChecktimer);
//do the actual work
var reqs = document.getElementById('requests');
var reqVal = reqs.get('value');
var buttons = $$('.clicker');
Array.each(buttons, function(va, index){
alert(va.get('value'));
});
}
}
}
</script>
This works well when the doc loads (as the results take a few seconds to arrive) but I need to narrow this down to the actual div contents, so other changes on the page do not fire the events.
I have tried:
var textNode = document.getElementById("sitepage_content_content");
textNode.addEventListener("DOMCharacterDataModified", function(evt) {
alert("Text changed");
}, false);
But the above does not return anything.
Can what I am trying to do be done in this way? If yes where am I going wrong?
Using Social Engine (Zend) framework with MooTools.
I did this in the end with a little cheat :-(
There is a google map loading on the page that sets markers to match the location of the results. So I added my events to the end this code namely: function setMarker() {}.
I will not mark this as the correct answer as it is not really an answer to my question, but rather a solution to my problem, which is localised to the Social engine framework.
I will add a Social engine tag to my original question in the hope it may help someone else in the future.
Thanks guys.

userscript: I lost some JS?

I do not understand what's going on...
I have a simple userscript, that add couple DIVs, css styles and JS functions in the pages I visit
In particular, I have one DIV that trigger a JS function with a onClick listener - this function is a "toggle" function (display/hide an other DIV):
function togglegm(etat) {
if (etat = 'on') {
document.getElementById('greasemky').style.display = 'block';
document.getElementById('greasemkytoggle').innerHTML = '';
} else if (etat = 'off') {
document.getElementById('greasemky').style.display = 'none';
document.getElementById('greasemkytoggle').innerHTML = '';
}
}
var script2 = d.createElement('script');
script2.appendChild(d.createTextNode(togglegm));
(d.body || d.head || d.documentElement).appendChild(script2);
The DIV "greasemkytoggle" only contains a link with a onClick that trigger "togglegm('on'), and my objective is that when togglegm(on) is executed, the innerHTML of this DIV becomes a trigger for togglegm(off).
Now the weird part... when I click on my DIV greasemkytoggle, the function togglegm(on) is perfectly executed (greasemky is displayed), and the innerHTML is perfectly changed with a link for "togglegm(off)", BUT if I click again, then nothing happens.
I looked at the source code, and discovered that my JS function just disappeared (that's why nothing happened on the last click)! Now, there is an empty function replacing my togglegm():
<script>
scriptHolderArray1
</script>
Do you understand that kind of behaviour...?
I found nothing online for that kind of situation...
GreaseMonkey runs under a much more security conscience set of rules.
Attach the event listeners using the proper DOM3 (addEventListener) method.
It is never a good idea (in user scripts or general scripting) to assign Javascript through innerHTML.
It is never a good idea to use the "javascript:" pseudo-protocol.
The problems are etat = 'on' and etat = 'off'.
If you want to set values, use
etat = 'on'
etat = 'off'
If you want to compare, use:
etat == 'on'
etat == 'off'
Moreover, href="javascript:return(false);" throws an error on Firefox because there is a return outside a function (SyntaxError: return not in function). You should do href="javascript:void(0);", or return false at the end of the onclick event.
Anyway, I don't understand very well what you are doing here:
var script2 = d.createElement('script');
script2.appendChild(d.createTextNode(togglegm));
(d.body || d.head || d.documentElement).appendChild(script2);
You have a function togglegm loaded to browser's memory by a <script> element.
Then, you create a new <script> with that function and append it to the document, in order to load it to browser's memory again (I guess).
Why?

Javascript - JQuery - clearInterval/setInterval - iframe cycle won't stop on click

I'm fairly new to Javascript in general, and I cobbled together a small script from things found mostly on this site to try to get a small iframe to cycle through a bunch of links, which it does brilliantly. However, I also want it to stop cycling when the user clicks on the iframe or any of its contents.
Here is the code I have so far. There is only one iframe on the HTML page.
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script type="text/javascript" charset="utf-8">
<!--
var sites = [
"side/html5.html",
"side/silverlight.html",
"side/wordpress.html",
"side/mysql.html",
"side/php.html",
"side/css3.html"
];
var currentSite = sites.length;
var timerId;
var iframeDoc = $("iframe").contents().get(0);
$(document).ready(function ()
{
var $iframe = $("iframe").attr("src","side/html5.html");
timerId = setInterval(function()
{
(currentSite == 0) ? currentSite = sites.length - 1 : currentSite = currentSite -1;
$iframe.attr("src",sites[currentSite]);
}, 4000);
$(iframeDoc).bind('click', function()
{
clearInterval(timerId);
});
});
//-->
</script>
</head>
<body>
<sidebar>
<iframe name="sideframe" src="side/html5.html"></iframe>
</sidebar> ..etc..
Please help, I am trying to learn Javascript as fast as I can but as far as I can see, it should work, but it really doesn't.
Thanks for any help you can give me, it's really appreciated.
EDIT:
Okay, I've got a new script now, mostly based off of Elias' work, but it doesn't work either. I've pinned it down in Firebug and it's saying that the timerCallback.currentSite value IS updating properly, though I can't find the $iframe's src value to check for it explicitly. As far as I can tell, it is updating the variables properly, it's just not updating the iframe properly. Am I calling/setting the iframe correctly in this code? Also, is the linked in jquery library sufficient for my purposes? I'm a little lost of all these libraries to link to...
<script type="text/javascript" src="http://code.jquery.com/jquery.js"></script>
<script type="text/javascript" charset="utf-8">
<!--
var sites =
[
"side/html5.html",
"side/silverlight.html",
"side/wordpress.html",
"side/mysql.html",
"side/php.html",
"side/css3.html"
];
var $iframe = $("iframe").attr("src","side/html5.html");
function timerCallback()
{
timerCallback.currentSite = (timerCallback.currentSite ? timerCallback.currentSite : sites.length) -1;
$iframe.attr("src",sites[timerCallback.currentSite]);
$($('iframe').contents().get('body')).ready(function()
{
$(this).unbind('click').bind('click',function()
{
var theWindow = (window.location !== window.parent.location ? window.parent : window);
theWindow.clearInterval(theWindow.timerId);
});
});
}
var timerId = setInterval(timerCallback, 4000);
//-->
</script>
If I were you, I'd play it safe. Since you say you're fairly new to JS, it might prove very informative.
function timerCallback()
{
timerCallback.currentSite = (timerCallback.currentSite ? timerCallback.currentSite : sites.length) -1;
$iframe.attr("src",sites[timerCallback.currentSite]);
}
var timerId = setInterval(timerCallback, 4000);
$($('iframe').contents().get('body')).unbind('click').bind('click', function()
{
var theWindow = (window.location !== window.parent.location ? window.parent : window);
theWindow.clearInterval(theWindow.timerId);
});
Now I must admit that this code is not tested, at all. Though I think it provides a couple of things to get you on your way:
1) the interval is set using a callback function, because it's just better for tons of reasons
1b) in that Callback, I took advantage of the fact that functions are objects, and created a static var, that is set to either the length of your sites array (when undefined or 0), in both cases 1 is substracted
2) jQuery's ,get() method returns a DOM element, not a jquery object, that's why I wrapped it in $(), a new jQ obj, giving you the methods you need.
3) since you're manipulating the dom inside the iFrame, it's best to unbind events you want to bind
4) inside the iFrame, you don't have direct access to the parent window, where your interval is.
You might want to read up on how to deal with iFrames, because they can be a bit of a faff from time to time
EDIT:
David Diez is right, easiest way around this is to incorporate the binding in the timeout function:
function timerCallback()
{
timerCallback.currentSide = ...//uncanged
//add this:
$($('iframe').contents().get('body')).ready(function()
{
$(this).unbind('click').bind('click',function()
{
//this needn't change
});
});
}
In theory, this should bind the click event to the body after it has been loaded
Edit2
I've been messing around a bit, you could keep your code, as is. just add a function:
function unsetInterval()
{
window.clearInterval(window.timerId);
}
and add this to your setInterval function:
$('#idOfIframe').load(function()
{
var parentWindow = window.parent;
$('body').on('click',function()
{
parentWindow.clearInterval();
});
});
this will get triggered as soon as the iFrame content is loaded, and bind the click event and unset the timer, like you wanted to
I think your code is not working because of this
var iframeDoc = $("iframe").contents().get(0);
This could be getting the header of the iFrame because you are saving the iframeDoc value to the first child of the iframe, the head tag, actually if you have more than 1 iframe in your window iframeDoc would be undefined because $("iframe") gets all the iframes of your document.
BTW your currentSite value condition is wrong, you asign the same value for both conditions
Now I give you an example:
<iframe id="myFrame" src="http://www.google.com/"></iframe>
and the script:
<script type="text/javascript" src="http://code.jquery.com/jquery.js"></script>
<script type="text/javascript">
var sites = [
"site1",
"site2"
];
var myFrame = document.getElementsByTagName('iframe')[0];
var currentSite = myFrame.getAttribute('src');
var timerId;
var myFrameDoc = window.frames[0].document;
$(document).ready(function()
{
myFrame.setAttribute('src', 'side/html5.html');
timerId = setInterval(function()
{
//WRONGG
(currentSite == 0) ? currentSite = sites.length - 1 : currentSite = currentSite -1;
myFrame.setAttribute('src', sites[currentSite]);
$(myFrame).off("click").on("click", clearInterval(timerId));
}, 4000);
//Won't work because you are trying to get events from an inside of a iframe
//$(myFrameDoc).on("click", clearInterval(timerId));
//This may work
$(myFrameDoc).off("click").on("click", clearInterval(timerId));
});
</script>
When you try to track the events of an iframe you have to be carefull because an iframe contains a totally different document for javascript purprouses so basically you have to get inside the new document, unbind the events you need to use, and bind them again against your functionality, as #Elias points out. but be aware that you are changing constantly the src of your iframe, so if yu really need to do that you will have to separate the code that unbinds and binds again your clearInterval, and for that matter maybe $.on() could work for you.
EDIT: Calling to the iframe should work this way IF the src of the iframe is inside the same domain, with the same port and with the same protocol:
var myFrameDoc = window.frames[0].document;
I Added a new variable because we want to bind and unbind the click event to the iframe's document, not to the iframe, we use for that the window.frames collection property, but modern browsers throw an exception and denies acces if you try to access to a frame and you are not on the same domain with using the same port and the same protocol...
Additionaly the use of $.on() and $.off() instead of $.bind and $.unbind() is because the first ones are the new ones and despite we are not using it here, they are capable of watch constantly the DOM for new elements to bind if added; that could be useful to this case if this code still doesn't work. If that is the case you can still change this:
var myFrameDoc = window.frames[0].window;
and this:
$(myFrameDoc).off("click", "document").on("click", "document", clearInterval(timerId));
This will re-bind the event handler to new documents additions. Not tested but could work.

Writing a custom javascript event

I'm writing some code that will get executed before the DOM loads, basically, using Modernizr to get scripts. Now my issue is that I want to show a loading animation if the DOM loads and the scripts are still loading.
Modernizr is executed in the head. If I put the code to use document.getElementById in the head also, error is thrown because the DOM hasn't loaded. Now I have no idea how to solve this.
Here is the code I have so far:
<head>
<script>
var FileManager = {
IsLoading = false;
LoadRequiredFiles: function (config) {
config = config || {};
this.OnLoading = config.onLoadingCallback;
this.OnComplete = config.onCompleteCallback;
this.IsLoading = true;
if (this.OnLoading) {
this.OnLoading();
}
var self = this;
Modernizr.load([{
load: '/jquery.min.js',
complete: function () {
if (self.OnComplete) {
self.OnComplete();
}
self.IsLoading = true;
}
},
]);
}
};
var globalLoadingId = 'globalLoader';
FileManager.LoadRequiredFiles({
onLoadingCallback: function () {
document.getElementById(globalLoadingId).style.display = 'block';
},
onCompleteCallback: function () {
document.getElementById(globalLoadingId).style.display = 'none';
}
});
</script>
I used to execute this code below the <body> tag, and it worked. Now I moved it into the <head>. So I used to pass 2 callbacks to it. Now I'd rather attach events to it and handle them in the body (assuming thats where the DOM is loaded).
What I'd like to do:
<head>
<script>
FileManager.LoadRequiredFiles();
</script>
</head>
<body>
<script>
//Bind the event, not sure if this is even possible in javascript.
FileManager.OnCompleted += fileManagerCompleted;
fileManagerCompleted()
{
document.getElementById(globalLoadingId).style.display = 'none';
}
if(FileManager.IsLoading)
{
document.getElementById(globalLoadingId).style.display = 'block';
}
</script>
</body>
The page is your canvas for display. You can't show anything before it loads. It sounds more like you want a very small page to load (quickly) where you could display your progress and then your code could dynamically load/display the rest of the page with ajax calls and javascript showing progress as it goes. That's the only way to get out in front of the rest of the page load that I know of.
The only entirely reliable way to run a script that manipulates the DOM is to use the body onload event. (window.onload is popular, but not quite 100% reliable.)
There are some browsers that implement a onDocumentReady event that can be kind-of-sort-of faked in IE, but I don't recommend its use.
Using getElementById will not, by itself, throw an error if used in the head. You might be causing an error because you aren't checking the returned value, which will be null if an element with the specified id wasn't found, e.g.
var el = document.getElementById('foo');
if (el) {
// do somethig with el
} else {
// el wasn't found
}
Your problem is how to display the image only if the scripts are still loading and the page is visible. The simple answer is don't use client-side script loading, do it at the server. :-)
If you want to persist with script loading, add a class to the loading image, say "hideOnLoad". Have a callback from the last script load that sets the rule to "display: none" (just create and add style sheet with that one rule using script).
Now you just include the loading image as the first element in the body with a class of "hideOnLoad", knowing that when scripts have finished loading they will hide the image regardless of whether it (or any other element with the same class) existed at the time or not.

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