Develop Reference

Dynamic Header Blur Filter

I have a fixed header that I would like to add a dynamic blur as the user scrolls down the page. I learned that the filter: blur(10px) only works for elements within the applied div.Could anyone point me in the right direction?
Updated: What I want to do is make anything that is underneath my fixed header appear blurred, not the actual header itself. I think I would have to make parts of the div under the header blurred rather than the whole div to achieve this effect.

Yes, add dynamicaly a classname with jquery.
http://api.jquery.com/scroll/
$(window).scroll(function() {
$( "#tag" ).addClass( "blurredclass" );
});
You can define a variable within scroll function to check offsetTop position, so you can add blurred class after you reach your position
var screenTop = $(document).scrollTop();
Edit: you can preview typical solution on JSFiddle
http://jsfiddle.net/x2N3N/1/
Edit2: if you want to blur text below some position while scrolling:
http://jsfiddle.net/x2N3N/2/
Edit3: variant with blurred header:
http://jsfiddle.net/x2N3N/3/

There is another option to help you solve your problem. If you want to blur the header background while scrolling the page (e.g. in iOS7 on iphone) the solution exists:
Using experimental methods:
http://codepen.io/FWeinb/full/Dfoaw
But problem is compatibility and speed:
Chrome 29+ (enable 'experimental-webkit-features'/'enable-experimental-web-platform-features')
Safari 6.1 Seed 6
iOS7 - slow
Next method is to blur rendered html in canvas
More info and example: http://blurpopup.labs.daum.net/
run html2canvas for rendering document as an image.
Convert image to data-url string and and place it as background-image.
apply blur (-webkit-filter:blur ... )
Append the bg layer into document with position of document scroll offset.
You can find html2canvas here: http://html2canvas.hertzen.com/ (it's a simple js library)
I've done complete live example with basic usage:
http://www.24development.cz/examples/blurred-header/
There are some limitations with html2canvas rendering, but for basic idea there is the point.

Detecting overflow content

I've tried to find an answer for a long time but I didn't find anything.
I'm using contentEditable div to write a text exactly on 210x297mm page. When page ends javascript adds next one:
if(container.scrollHeight > container.clientHeight)
{
page_number = page_number+1
$('#editor').append('<div id="page_'+page_number+'" class="page" onkeyup="javascript:check_page(this);" contentEditable></div><div class="marginbottom"></div>');
$("#page_"+page_number).attr("tabindex",-1).focus();
}
Everything works fine, unless I paste any longer text inside the div at the end of each page. Then only the part of the text apears and the rest goes outside div (and because of 'overflow: hidden' is invisible).
Is there any javascript/jquery method to detect overflow's content and move it into the next page (I didn't find it) or any CSS style that will allow me to separate the text inside each div?
I've read about CSS3 multi-column and I need sth doing similar operations, but separating rows, not columns.

I think your best bet is to not use overflow: hidden but auto and try to detect with JavaScript if there's an overflow by checking for scroll height.
In this case you can dynamically start moving parts of the text (word by word maybe) until the content can fit the available space.
For some concrete techniques check this thread out for example: detect elements overflow using jquery

Force scrollbar to bottom

I am making a little messaging / chat system that is working nice and fine. The problem is, the <div> which the messages are outputted to does not scroll the way I need it to.
All the new messages are added to the bottom of the div and when more are added and the scrollbar shows up, the scrolling stays at the top of the <div>. I need this to be reversed, so that the scrolling always sticks to the bottom of the <div>.
A good example of what I want would be Steam's chat windows, or even this text input which I am using to fill out the question.
As I would like to avoid jQuery, this has me completely stuck. If you could point me in the correct direction that would be great! I am not sure if HTML and CSS can handle this, or if JavaScript is necessary at all.

The Javascript code below should keep your div's scrollbar positioned at the bottom like you described:
var objDiv = document.getElementById("divExample");
objDiv.scrollTop = objDiv.scrollHeight;
This solution and more information can be found on the link below:
http://web.archive.org/web/20080821211053/http://radio.javaranch.com/pascarello/2005/12/14/1134573598403.html

I think this is a better solution:
element.scrollTop = element.scrollHeight - element.clientHeight;

For Kotlin I have used the following:
val element = view?.findViewById<ScrollView>(R.id.uidScrollElement)
element?.smoothScrollTo(0,element.measuredHeight)

full div area onclick

This problem was not solved.. it was just evaded.. so dont use this as reference
what i have is
<div>
<img onclick='this.style.display="none";this.parentNode.getElementsByTagName("div")[0].style.display="block";this.parentNode.getElementsByTagName("div")[0].style.width=this.offsetWidth+"px";this.parentNode.getElementsByTagName("div")[0].style.height=this.height+"px";' src='http://static.***.pl/cache/***.pl/math/cafc682a15c9c6f1b7bb41eb004d6c45935cbf06434221f7201665f85242cb94.png'/>
<div onclick='this.style.display="none";this.parentNode.getElementsByTagName("img")[0].style.display="inline";' style='display:none'>
<pre style='width:100%;height:100%;'>
\lim_{t\to\infty}\int\limits_1^{t} \frac{1}{x^2}\,dx=\lim_{t\to\infty}\left(-\frac{1}{x}\right)\bigg|_1^t=\lim_{t\to\infty}\left(-\frac{1}{t}-\left(-\frac{1}{1}\right)\right)=\kappa=1880154404
</pre>
</div>
</div>
yes i know its ugly but well..
my problem is when i click the image it does what i want but if i then click the div it only works if i click on the text and i want it to work for the full div !
i dont want to use document.getElementById etc...
there will be multiple instances of this code and it will be in unknown places.
i really dont want to write up bloated code to do this (this includes jQuery,flash,.NET, Zend Engine etc etc...)
my question is simple :
why the hell does it work only if i click on text and how to fire onclick for the whole div

In your original Javascript action, you were setting the width and height of your div to zero, which means that there is no area to click on.
Here is a demo: http://jsfiddle.net/audetwebdesign/ndKqM/
which should demonstrate the fix. I added some background color and padding to show the dimensions of the various boxes.
I removed the parts of the JS that calculated width and height and that fixed the issue.
If you click on the lime green area that holds your text, the action works.
Unless there is some other reason, you don't need to adjust width or height.

It's hard to tell what behavior you really want.
You are setting the image to display:none, and then you set the style.height and style.width of the sibling div to image.height and image.width. So - those will both be zero (as display:none is set for the image).
Do yourself a favor and set background colors or borders for your divs so you can see what's going on as you code.

Use an A tag with your onclick event and a null URL href="javascript://" instead of a DIV

jQuery Slide Toggle Not Working - Resolved

On the first click, it works as expected:
the class is changed
and the html content is changed from 'Show...' to 'Close...'
the content area is expanded with the slideDown effect,
Good so far.
On the second click, ...
the class changes
the html content is changed from 'Close...' to 'Show...'
The content area does NOT go away as expected.
On the third click, ...
the class is changed
the html content is changed
the already-shown content is re-shown with the slidedown effect.
So everything is working except for the 2nd click when the content is supposed to be hidden again.
Here's the jQuery:
-
$('.open_user_urls').live('click', function() {
$('#user_urls').slideDown('slow');
$(this).addClass('close_user_urls');
$(this).removeClass('open_user_urls');
$(this).html('Close Search History');
return false;
});
$('.close_user_urls').live('click', function() {
$('#user_urls').slideUp('slow');
$(this).addClass('open_user_urls');
$(this).removeClass('close_user_urls');
$(this).html('Show Search History');
return false;
});
Here's the HTML it's acting on:
<h3 class='open_user_urls'>Show Search History</h3>
<div id='user_urls'>
// an OL tag with content
</div>
And the only applicable CSS:
#user_urls { display: none; }
EDIT - I replaced my jquery code with functionally equivalent code supplied in an answer below, but the problem persists. So the cause must be elsewhere. I do recall this code working originally, but then it stopped. I'm stumped. Time to strip everything else out piece by piece...
EDIT 2 - Since the bug must be elsewhere, I'm accepting a code improvement for my jquery as the answer. Thanks.
Edit 3 - Found the source of the problem.
Inside the #user_urls div I have an series of OLs with the following css:
.url_list {float: left; width: 285px; list-style-position: outside; margin-left: 25px;}
Each OL contains a list of 20 urls and is meant to display in as many multiple columns as required to display all the URLs.
Removing the float: left; on these OL tags causes the problem to go away.
So having a float on the content contained in the DIV thats showing and hiding is causing it not not hide at all. Why would this happen?
EDIT 4: Adding a inside the #user_urls DIV allows the hiding action to work properly.

Perhaps something like this would be simpler?
$(".open_user_urls").toggle(
function () {
$(this).text("Close Search History").siblings(".user_urls").slideDown("slow");
},
function () {
$(this).text("Show Search History").siblings(".user_urls").slideUp("slow");
}
);
The toggle function is designed for precisely the scenario you're encountering.

To reiterate the problem and resolution to this question...
Inside the #user_urls DIV were a series of OL tags, each floated left. It was the float that was causing the problem.
Adding a <br style='clear: left;' /> inside the #user_urls DIV fixed the problem.

From what I've found, jQuery needs to have the height style set in order to slide it correctly. A work around I've used is to set the height before you slide it closed.
$('#user_urls').css('height', $('#user_urls').height() + 'px');
After you set it once, it should work correctly from then on. Check out this tutorial for a more detailed explanation.

Since this question was opened, jQuery have put in a fix for this themselves.
Updating to the latest version of jQuery solved the problem for us with no CSS changes. (jQuery 1.4.4 as of Dec 9th 2010)
Found via discussion on Google Groups in turn found from d12's answer. According to duscussion, in some jQuery 1.3x versions this bug affected several actions, slideUp, fadeOut, and toggle, if the element being hidden/slid up is a a non-floated parent containing floated children.

I think Conor's answer might put you on the right track. I might also suggest slideToggle and toggleClass:
http://docs.jquery.com/Attributes/toggleClass
http://docs.jquery.com/Effects/slideToggle
I could be as easy as:
$("h3.open_user_urls").click(function () {
next("div#user_urls").slideToggle();
});

I can't duplicate your bug. I used your exact code and I cannot replicate your issue.
This must be a script error from a different place in your JS code.

Thanks for this question. It really got me on my way figuring out the problem toggling an element with floated children.
Another resource that really helped and explains the behavior a bit can be found
on this Google group discussion.

Putting a non breaking space in your div is another solution similar to what The Reddest suggested that worked for me on a similar issue.