Develop Reference

Resize window with smooth transition for different height sizes

Some context:
I'm working on a Chrome Extension where the user can launch it via default "popup.html", or if the user so desires this Extension can be detached from the top right corner and be used on a popup window via window.open
This question will also apply for situations where users create a Shortcut for the extension on Chrome via:
"..." > "More tools" > "Create Shortcut"
Problem:
So what I need is for those cases where users use the extension detached via window.open or through a shortcut, when navigating through different options, for the Height of the window to be resized smoothly.
I somewhat achieve this but the animation is clunky and also the final height is not always the same. Sometimes I need to click twice on the button to resize too because 1 click won't be enough. Another issue is there is also some twitching of the bottom text near the edge of the window when navigating.
Here's what I got so far:
(strWdif and strHdif are used to compensate for some issues with CSS setting proper sizes which I haven't figured out yet.)
const popup = window;
function resizeWindow(popup) {
setTimeout(function () {
var strW = getComputedStyle(window.document.querySelector(".body_zero")).getPropertyValue("width");
var strW2 = strW.slice(0, -2);
var strWdif = 32;
var bodyTargetWidth = (parseFloat(strW2) + parseFloat(strWdif));
var strH = getComputedStyle(window.document.querySelector(".body_zero")).getPropertyValue("height");
var strH2 = strH.slice(0, -2);
var strHdif = 54;
var bodyTargetHeight = (parseFloat(parseInt(strH2)) + parseFloat(strHdif));
var height = window.innerHeight;
console.log("Window Height: ", height, "CSS Height: ", bodyTargetHeight);
var timer = setInterval(function () {
if (height < bodyTargetHeight) {
popup.resizeTo(bodyTargetWidth, height += 5);
if (height >= bodyTargetHeight) {
clearInterval(timer);
}
} else if (height > bodyTargetHeight) {
popup.resizeTo(bodyTargetWidth, height -= 5);
if (height <= bodyTargetHeight) {
clearInterval(timer);
}
} else {
clearInterval(timer);
}
}, 0);
}, 0400);
}
Question:
Is there a way to make this more responsive, and smooth and eliminate all the twitching and clunkiness?
I guess the issue might be that I am increasing/diminishing by 5 pixels at a time but that is the speed I need. Maybe there is another way to increase/decrease by 1px at a faster rate? Could this be the cause of the twitching and clunkiness?
Also, I should add that troubleshooting this is difficult because the browser keeps crashing so there is also a performance issue sometimes when trying different things.
EDIT:
Another option using resizeBy:
function animateClose(time) {
setTimeout(function () {
var strW = getComputedStyle(window.document.querySelector(".body_zero")).getPropertyValue("width");
var strW2 = strW.slice(0, -2);
var strWdif = 32;
var bodyTargetWidth = (parseFloat(strW2) + parseFloat(strWdif));
var strH = getComputedStyle(window.document.querySelector(".body_zero")).getPropertyValue("height");
var strH2 = strH.slice(0, -2);
var strHdif = 54;
var bodyTargetHeight = (parseFloat(parseInt(strH2)) + parseFloat(strHdif));
var w = window.innerWidth; //Get window width
var h = window.innerHeight; //Get window height
var loops = time * 0.1; //Get nb of loops
var widthPercentageMinus = (w / loops) * -0;
var heightPercentageMinus = (h / loops) * -1;
var widthPercentagePlus = (w / loops) * +0;
var heightPercentagePlus = (h / loops) * +1;
console.log("Window Height: ", h, "CSS Height: ", bodyTargetHeight);
var loopInterval = setInterval(function () {
if (h > bodyTargetHeight) {
window.resizeBy(widthPercentageMinus, heightDecrheightPercentageMinuseasePercentageMinus);
} else if (h < bodyTargetHeight) {
window.resizeBy(widthPercentagePlus, heightPercentagePlus);
} else {
clearInterval(loopInterval);
}
}, 1);
}, 0400);
}
This one is a bit more smooth but I can't make it stop at the desired Height. It also is not differentiating between resizing up or down, also crashes the browser sometimes.

maybe with requestAnimationFrame
try something like this (not tested):
function resizeWindow(popup) {
var gcs = getComputedStyle(window.document.querySelector(".body_zero"));
var strW = gcs.getPropertyValue("width");
var strW2 = strW.slice(0, -2);
var strWdif = 32;
var bodyTargetWidth = (parseFloat(strW2) + parseFloat(strWdif));
var strH = gcs.getPropertyValue("height");
var strH2 = strH.slice(0, -2);
var strHdif = 54;
var bodyTargetHeight = (parseFloat(parseInt(strH2)) + parseFloat(strHdif));
var height = window.innerHeight;
console.log("Window Height: ", height, "CSS Height: ", bodyTargetHeight);
window.myRequestAnimationFrame = window.requestAnimationFrame || window.webkitRequestAnimationFrame;
var hStep = 2; //choose the step. Must be an integer
function internalFunc() {
if (Math.abs(height - bodyTargetHeight) > hStep) {
if (height < bodyTargetHeight)
hStep *= 1;
else if (height > bodyTargetHeight)
hStep *= -1;
popup.resizeBy(0, hStep);
height += hStep;
window.myRequestAnimationFrame(internalFunc)
} else
popup.resizeBy(0, bodyTargetHeight - height)
}
popup.resizeTo(bodyTargetWidth, height);
window.myRequestAnimationFrame(internalFunc)
}

<html>
<head>
<script>
const bodyTargetWidth = 150;
const bodyTargetHeight = 250; //target height
var height; //height at beginning
window.myRequestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame;
var hStep = 5; //choose the step. Must be an integer
var dir;
var myPopup;
function doResize() {
function internalFunc() {
console.log('height: ', height) ;
if (Math.abs(height - bodyTargetHeight) > hStep) {
dir = Math.sign(bodyTargetHeight - height);
myPopup.resizeBy(0, dir * hStep);
height += dir * hStep;
window.myRequestAnimationFrame(internalFunc)
} else
myPopup.resizeBy(0, bodyTargetHeight - height)
}
if (!myPopup || myPopup?.closed) {
myPopup = window.open("about:blank", "hello", "left=200,top=200,menubar=no,status=no,location=no,toolbar=no");
height = 150;
myPopup.resizeTo(bodyTargetWidth, height);
} else {
myPopup.focus();
height = myPopup.outerHeight
}
myPopup.resizeTo(bodyTargetWidth, height);
window.myRequestAnimationFrame(internalFunc)
}
document.addEventListener('DOMContentLoaded', _ => document.getElementById('myBtn').addEventListener('click', doResize))
</script>
</head>
<body>
<button type="button" id="myBtn">Create popup<br>\<br>Reset popup height</button><br>
<p>First create the popup, then change popup height and click the button above again</p>
</body>
</html>

1000 DOM elements on a single page

For a project of big "text map" BigPicture, I need to have more than 1000 text inputs.
When you click + drag, you can "pan" the displayed area.
But the performance is very poor (both on Firefox and Chrome) : rendering 1000+ DOM elements is not fast at all.
Of course, another solution with better performance would be : work on a <canvas>, render text as bitmap on it, and each time we want to edit text, let's show a unique DOM <textarea>, that disappears what editing is finished, and text is rendered as bitmap again... It works (I'm currently working in this direction) but it needs much more code in order to provide editing on a canvas.
Question : Is it possible to improve performance for rendering of 1000+ DOM elements on a HTML page, so that I don't need to use <canvas> at all ?
Or will it be impossible to have good performance when panning a page with 1000+ DOM elements ?
Notes :
1) In the demo here I use <span contendteditable="true"> because I want multiline input + autoresize, but the rendering performance is the same with standard <textarea>.*
2) For reference, this is how I create the 1000 text elements.
for (i=0; i < 1000; i++)
{
var blax = (Math.random()-0.5)*3000;
var blay = (Math.random()-0.5)*3000;
var tb = document.createElement('span');
$(tb).data("x", blax / $(window).width());
$(tb).data("y", blay / $(window).height());
$(tb).data("size", 20 * currentzoom);
tb.contentEditable = true;
tb.style.fontFamily = 'arial';
tb.style.fontSize = '20px';
tb.style.position = 'absolute';
tb.style.top = blay + 'px';
tb.style.left = blax + 'px';
tb.innerHTML="newtext";
document.body.appendChild(tb);
}

For something like this you could make use of document fragment, these are DOM nodes that are not part of the actually DOM tree (more info can be found here https://developer.mozilla.org/en-US/docs/Web/API/document.createDocumentFragment), so you can do all your setup on the fragment and then append the fragment which will only be causing the one re flow rather than 1000.
So here is an example -http://jsfiddle.net/leighking2/awzoz7bj/ - a quick check on run time it takes around 60-70ms to run
var currentzoom = 1;
var docFragment = document.createDocumentFragment();
var start = new Date();
for (i=0; i < 1000; i++)
{
var blax = (Math.random()-0.5)*3000;
var blay = (Math.random()-0.5)*3000;
var tb = document.createElement('span');
$(tb).data("x", blax / $(window).width());
$(tb).data("y", blay / $(window).height());
$(tb).data("size", 20 * currentzoom);
tb.contentEditable = true;
tb.style.fontFamily = 'arial';
tb.style.fontSize = '20px';
tb.style.position = 'absolute';
tb.style.top = blay + 'px';
tb.style.left = blax + 'px';
tb.innerHTML="newtext";
docFragment.appendChild(tb);
}
document.body.appendChild(docFragment);
var end = new Date();
console.log(end-start)
compared to the original which took around 645ms to run http://jsfiddle.net/leighking2/896pusex/
UPDATE So for improving the dragging speed again keep the individual edits out of the DOM to avoid the cost of the reflow 1000 times every mouse drag
so here is one way using jquery's detach() method (example http://jsfiddle.net/sf72ubdt/). This will remove the elements from the DOM but give them to you with all their properties so you can manipulate them and reinsert them later on
redraw = function(resize) {
//detach spans
var spans = $("span").detach();
//now loop other them, because they are no longer attached to the DOM any changes are
//not going to cause a reflow of the page
$(spans).each(function(index) {
var newx = Math.floor(($(this).data("x") - currentx) / currentzoom * $(window).width());
var newy = Math.floor(($(this).data("y") - currenty) / currentzoom * $(window).height());
if (resize) {
displaysize = Math.floor($(this).data("size") / currentzoom);
if (displaysize) {
$(this).css({
fontSize: displaysize
});
$(this).show();
} else
$(this).hide();
}
//changed this from offset as I was getting a weird dispersing effect around the mouse
// also can no longer test for visible but i assume you want to move them all anyway.
$(this).css({
top: newy + 'px',
left: newx + 'px'
});
});
//reattach to the body
$("body").append(spans);
};
UPDATE 2 -
So to get a little more performance out of this you can cache the window width and height, use a vanilla for loop, use vanilla js to change the css of the span. Now each redraw (on chrome) takes around 30-45 ms (http://jsfiddle.net/leighking2/orpupsge/) compared to my above update which saw them at around 80-100ms (http://jsfiddle.net/leighking2/b68r2xeu/)
so here is the updated redraw
redraw = function (resize) {
var spans = $("span").detach();
var width = $(window).width();
var height = $(window).height();
for (var i = spans.length; i--;) {
var span = $(spans[i]);
var newx = Math.floor((span.data("x") - currentx) / currentzoom * width);
var newy = Math.floor((span.data("y") - currenty) / currentzoom * height);
if (resize) {
displaysize = Math.floor(span.data("size") / currentzoom);
if (displaysize) {
span.css({
fontSize: displaysize
});
span.show();
} else span.hide();
}
spans[i].style.top = newy + 'px',
spans[i].style.left = newx + 'px'
}
$("body").append(spans);
};
SNIPPET EXAMPLE -
var currentzoom = 1;
var docFragment = document.createDocumentFragment();
var start = new Date();
var positions = []
var end = new Date();
console.log(end - start);
var currentx = 0.0,
currenty = 0.0,
currentzoom = 1.0,
xold = 0,
yold = 0,
button = false;
for (i = 0; i < 1000; i++) {
var blax = (Math.random() - 0.5) * 3000;
var blay = (Math.random() - 0.5) * 3000;
var tb = document.createElement('span');
$(tb).data("x", blax / $(window).width());
$(tb).data("y", blay / $(window).height());
$(tb).data("size", 20 * currentzoom);
tb.contentEditable = true;
tb.style.fontFamily = 'arial';
tb.style.fontSize = '20px';
tb.style.position = 'absolute';
tb.style.top = blay + 'px';
tb.style.left = blax + 'px';
tb.innerHTML = "newtext";
docFragment.appendChild(tb);
}
document.body.appendChild(docFragment);
document.body.onclick = function (e) {
if (e.target.nodeName == 'SPAN') {
return;
}
var tb = document.createElement('span');
$(tb).data("x", currentx + e.clientX / $(window).width() * currentzoom);
$(tb).data("y", currenty + e.clientY / $(window).height() * currentzoom);
$(tb).data("size", 20 * currentzoom);
tb.contentEditable = true;
tb.style.fontFamily = 'arial';
tb.style.fontSize = '20px';
tb.style.backgroundColor = 'transparent';
tb.style.position = 'absolute';
tb.style.top = e.clientY + 'px';
tb.style.left = e.clientX + 'px';
document.body.appendChild(tb);
tb.focus();
};
document.body.onmousedown = function (e) {
button = true;
xold = e.clientX;
yold = e.clientY;
};
document.body.onmouseup = function (e) {
button = false;
};
redraw = function (resize) {
var start = new Date();
var spans = $("span").detach();
var width = $(window).width();
var height = $(window).height();
for (var i = spans.length; i--;) {
var span = $(spans[i]);
var newx = Math.floor((span.data("x") - currentx) / currentzoom * width);
var newy = Math.floor((span.data("y") - currenty) / currentzoom * height);
if (resize) {
displaysize = Math.floor(span.data("size") / currentzoom);
if (displaysize) {
span.css({
fontSize: displaysize
});
span.show();
} else span.hide();
}
spans[i].style.top = newy + 'px',
spans[i].style.left = newx + 'px'
}
$("body").append(spans);
var end = new Date();
console.log(end - start);
};
document.body.onmousemove = function (e) {
if (button) {
currentx += (xold - e.clientX) / $(window).width() * currentzoom;
currenty += (yold - e.clientY) / $(window).height() * currentzoom;
xold = e.clientX;
yold = e.clientY;
redraw(false);
}
};
$(function () {
$('body').on('mousedown', 'span', function (event) {
if (event.which == 3) {
$(this).remove()
}
})
});
zoomcoef = function (coef) {
middlex = currentx + currentzoom / 2
middley = currenty + currentzoom / 2
currentzoom *= coef
currentx = middlex - currentzoom / 2
currenty = middley - currentzoom / 2
redraw(true)
}
window.onkeydown = function (event) {
if (event.ctrlKey && event.keyCode == 61) {
zoomcoef(1 / 1.732);
event.preventDefault();
}
if (event.ctrlKey && event.keyCode == 169) {
zoomcoef(1.732);
event.preventDefault();
}
if (event.ctrlKey && event.keyCode == 48) {
zoomonwidget(1 / 1.732);
event.preventDefault();
}
};
html, body {
height: 100%;
width: 100%;
margin: 0;
padding: 0;
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>

A solution was given by #Shmiddty which is much faster to all previous attempts : all elements should be wrapped, and only the wrapper has to be moved (instead of moving each element) :
http://jsfiddle.net/qhskacsw/
It runs smooth and fast even with 1000+ DOM elements.
var container = document.createElement("div"),
wrapper = document.createElement("div"),
dragging = false,
offset = {x:0, y:0},
previous = {x: 0, y:0};
container.style.position = "absolute";
wrapper.style.position = "relative";
container.appendChild(wrapper);
document.body.appendChild(container);
for (var i = 1000, span; i--;){
span = document.createElement("span");
span.textContent = "banana";
span.style.position = "absolute";
span.style.top = (Math.random() * 3000 - 1000 | 0) + 'px';
span.style.left = (Math.random() * 3000 - 1000 | 0) + 'px';
wrapper.appendChild(span);
}
// Don't attach events like this.
// I'm only doing it for this proof of concept.
window.ondragstart = function(e){
e.preventDefault();
}
window.onmousedown = function(e){
dragging = true;
previous = {x: e.pageX, y: e.pageY};
}
window.onmousemove = function(e){
if (dragging){
offset.x += e.pageX - previous.x;
offset.y += e.pageY - previous.y;
previous = {x: e.pageX, y: e.pageY};
container.style.top = offset.y + 'px';
container.style.left = offset.x + 'px';
}
}
window.onmouseup = function(){
dragging = false;
}

IMHO, I would go with your current thinking to maximize performance.
Reason: 1000+ DOM elements will always limit performance.
Yes, there is slightly more coding but your performance should be much better.
create one large offscreen canvas containing all 1000 texts.
Use context.textMeasure to calculate the bounding box of all 1000 texts relative to the image.
Save the info about each text in an object
var texts=[];
var texts[0]={ text:'text#0', x:100, y:100, width:35, height:20 }
...
context.drawImage that image on a canvas using an offset-X to 'pan' the image. This way you only have 1 canvas element instead of 1000 text elements.
In the mousedown handler, check if the mouse position is inside the bounding box of any text.
If the mouse is clicked inside a text bounding box, absolutely position an input-type-text directly over the text on the canvas. This way you only need 1 input element which can be reused for any of the 1000 texts.
Use the abilities of the input element to let the user edit the text. The canvas element has no native text editing abilities so don't "recreate the wheel" by coding canvas text editing.
When the user is done editing, recalculate the bounding box of the newly edited text and save it to the text object.
Redraw the offscreen canvas containing all 1000 texts with the newly edited text and draw it to the onscreen canvas.
Panning: if the user drags the onscreen canvas, draw the offscreen canvas onto the onscreen canvas with an offset equal to the distance the user has dragged the mouse. Panning is nearly instantaneous because drawing the offscreen canvas into the onscreen canvas-viewport is much, much faster than moving 1000 DOM input elements
[ Addition: full example with editing and panning ]
**Best Viewed In Full Screen Mode**
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var $canvas=$("#canvas");
var canvasOffset=$canvas.offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var texts=[];
var fontSize=12;
var fontFace='arial';
var tcanvas=document.createElement("canvas");
var tctx=tcanvas.getContext("2d");
tctx.font=fontSize+'px '+fontFace;
tcanvas.width=3000;
tcanvas.height=3000;
var randomMaxX=tcanvas.width-40;
var randomMaxY=tcanvas.height-20;
var panX=-tcanvas.width/2;
var panY=-tcanvas.height/2;
var isDown=false;
var mx,my;
var textCount=1000;
for(var i=0;i<textCount;i++){
var text=(i+1000);
texts.push({
text:text,
x:parseInt(Math.random()*randomMaxX),
y:parseInt(Math.random()*randomMaxY)+20,
width:ctx.measureText(text).width,
height:fontSize+2,
});
}
var $textbox=$('#textbox');
$textbox.css('left',-200);
$textbox.blur(function(){
$textbox.css('left',-200);
var t=texts[$textbox.textsIndex]
t.text=$(this).val();
t.width=ctx.measureText(t.text).width;
textsToImage();
});
textsToImage();
$("#canvas").mousedown(function(e){handleMouseDown(e);});
$("#canvas").mousemove(function(e){handleMouseMove(e);});
$("#canvas").mouseup(function(e){handleMouseUpOut(e);});
$("#canvas").mouseout(function(e){handleMouseUpOut(e);});
// create one image from all texts[]
function textsToImage(){
tctx.clearRect(0,0,tcanvas.width,tcanvas.height);
for(var i=0;i<textCount;i++){
var t=texts[i];
tctx.fillText(t.text,t.x,t.y)
tctx.strokeRect(t.x,t.y-fontSize,t.width,t.height);
}
redraw();
}
function redraw(){
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.drawImage(tcanvas,panX,panY);
}
function handleMouseDown(e){
e.preventDefault();
e.stopPropagation();
mx=parseInt(e.clientX-offsetX);
my=parseInt(e.clientY-offsetY);
// is the mouse over a text?
var hit=false;
var x=mx-panX;
var y=my-panY;
for(var i=0;i<texts.length;i++){
var t=texts[i];
if(x>=t.x && x<=t.x+t.width && y>=t.y-fontSize && y<=t.y-fontSize+t.height){
$textbox.textsIndex=i;
$textbox.css({'width':t.width+5, 'left':t.x+panX, 'top':t.y+panY-fontSize});
$textbox.val(t.text);
$textbox.focus();
hit=true;
break;
}
}
// mouse is not over any text, so start panning
if(!hit){isDown=true;}
}
function handleMouseUpOut(e){
e.preventDefault();
e.stopPropagation();
isDown=false;
}
function handleMouseMove(e){
if(!isDown){return;}
e.preventDefault();
e.stopPropagation();
var mouseX=parseInt(e.clientX-offsetX);
var mouseY=parseInt(e.clientY-offsetY);
panX+=mouseX-mx;
panY+=mouseY-my;
mx=mouseX;
my=mouseY;
redraw();
}
body{ background-color: ivory; padding:10px; }
#wrapper{position:relative; border:1px solid blue; width:600px; height:600px;}
#textbox{position:absolute;}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<h4>Click on #box to edit.<br>Tab to save changes.<br>Drag on non-text.</h4><br>
<div id=wrapper>
<input type=text id=textbox>
<canvas id="canvas" width=600 height=600></canvas>
</div>
<button></button>

I just run couple tests and it seems that moving absolutely positioned (position:absolute;) DOM elements (divs) with CSS transform:translate is even faster (by about 30%) than doing it via Canvas. But I was using CreateJS framework for the canvas job so my results may not hold for other use cases.

Using the window resize function to keep variables uptodate?

I am a little confused on how to keep some variables Ive created uptodate when the window is resized so my scroll function carries on getting the correct values. Basically I have multiple elements that contain a message that gets displayed when the user scrolls the element into 50% height of the viewport height. This works fine but my issue is when I resize I'm not sure how to update my variables boxHeight, elementOffset, verticalMatch which keep control of the values I need to use in my scroll event. I was wondering can someone help explain how I can resolve this?
My code looks like this
var windowHeight = $(window).height(),
headerHeight = $('.header').height();
$('.box').each(function (i,e) {
var el = $(e);
var boxHeight = el.height(),
elementOffset = el.offset().top,
verticalMatch = (windowHeight / 2) + (headerHeight / 2) - (boxHeight / 2);
$(window).on('scroll', function () {
var scrollTop = $(window).scrollTop(),
distance = elementOffset - scrollTop;
if( distance <= verticalMatch ) {
el.addClass('is-active');
}
});
});
$(window).on('resize', function() {
windowHeight = $(window).height()
elementOffset = $('.box').offset().top;
$('.box').each(function (i,e) {
var el = $(e);
//update boxHeight, elementOffset, verticalMatch
verticalMatch = (windowHeight / 2) + (headerHeight / 2) - (boxHeight / 2);
});
});
And heres the JS Fiddle: http://jsfiddle.net/fm4z7/2/
If someone could explain how I do this it would be great!

If all you want to do is update your sizing variables during a resize event, then do just that:
$(window).on('resize', function() {
windowHeight = $(window).height();
elementOffset = $('.box').offset().top;
});
Your variables are global so they can be accessed anywhere.

IE8 jQ set CSS properties (width or margin) are getting ignored

Today I've encountered an interesting situation with IE8 while I was trying to manipulate images.
I'm replacing loaded images by changing their url and when they get loaded I'm trying to properly squeeze them and center at viewport element (new images are not square as their predecessors).
But in IE8 (haven't tested IE7, and heard from colleagues IE9 - is all fine) images are not scaled, they just drop at their original size and my
img.height(105);
img.css('margin-left', (shift?-shift:0));
are simply ignored.
Here is the code snipped with the problem.
$('.people-images img').each(function () {
var img = $(this);
var oUrl = img.attr('src');
oUrl = oUrl.replace(/[SM]Thumb/, 'LThumb');
img.bind('load', function () {
var img = $(this);
if (this.width > this.height) {
var shift = (this.width / (this.height / 105) - 105) / 2;
img.height(105);
img.css('margin-left', (shift?-shift:0));
}
else {
var shift = (this.height / (this.width / 105) - 105) / 2;
img.width(105);
img.css('margin-top', (shift?-shift:0));
}
});
img.attr('src', oUrl);
img.attr('style', null);
img.parent().attr('style', null);
});
Please look for my self-answer for the solution.

The problem turned out to be IE image cache and the way it handles event handlers.
The css were cleared by myself at this line img.attr('style', null);. So simply moving this style deletion at top solved the problem.
$('.people-images img').each(function () {
var img = $(this);
var oUrl = img.attr('src');
oUrl = oUrl.replace(/[SM]Thumb/, 'LThumb');
img.attr('style', null);
img.bind('load', function () {
var img = $(this);
if (this.width > this.height) {
var shift = (this.width / (this.height / 105) - 105) / 2;
img.height(105);
img.css('margin-left', (shift?-shift:0));
}
else {
var shift = (this.height / (this.width / 105) - 105) / 2;
img.width(105);
img.css('margin-top', (shift?-shift:0));
}
});
img.attr('src', oUrl);
img.parent().attr('style', null);
});
I find this quite odd, cause even if cached images do get loaded immediately how come IE triggers callback in the middle of the execution scope?
Guess, placing style related code just before the src replacement should also work, but I didn't confirm that.
img.attr('style', null);
img.attr('src', oUrl);
Hope this helps!

"Zooming" elements on a page while keeping the centre of enlargement in the centre of the window

I'm trying to work out how to enlarge all elements on a page, but keep the centre of enlargement in the centre of the window.
On this page, once the image reaches the top or the left side of the window the centre of enlargement changes. It also changes when you move the image. (exactly what you would expect)
I'm thinking I'd need to take a completely different approach to achieve what I want. But I'm not sure what that approach is..
Any ideas?

Well, here's my take.
Only thing is that I ditched the containers you were using. Is that cheating? Seems like they were only there to get the image centered. No need.
This works as expected with no side effects.
Here's a working demo you can test:
http://jsfiddle.net/YFPRB/1/
(You need to click on the pane with the baboon first.)
HTML
<body>
<img src="http://cdn.sstatic.net/stackoverflow/img/apple-touch-icon.png" />
</body>
CSS
html, body {
width: 100%;
height: 100%;
overflow: hidden;
}​
jQuery
EDIT: Thanks to #stagas for the reminder to clean up redundancies.
var $img = $('img'); // Cache the image. Better for performance.
$img.draggable();
$img.css({left: ($('body').width() / 2) - ($img.width() / 2)})
.css({top: ($('body').height() / 2) - ($img.height() / 2)})
$(document).keydown(function(event) {
if (event.keyCode == 38) {
var adjustment = 1.25;
} else if (event.keyCode == 40) {
var adjustment = 0.8;
} else {
return;
}
var offset = $img.offset();
var width = $img.width();
var height = $img.height();
var newWidth = width * adjustment;
var newHeight = height * adjustment;
var diffWidth = newWidth - width;
var diffHeight = newHeight - height;
var hcenter = $('body').width() / 2;
var vcenter = $('body').height() / 2;
var leftPercent = (hcenter - offset.left) / width;
var topPercent = (vcenter - offset.top) / height;
$img.offset({top: offset.top - (diffHeight * topPercent), left: offset.left - (diffWidth * leftPercent)});
$img.width(newWidth).height(newHeight);
});​

This is what I came up, it works as you say except the image will always go to the center after zooming in or out:
$('document').ready(function() {
zoomimg=$('#zoomimg'); // we store this in a variable since we don't need to traverse the DOM every time -- this is faster
var viewportWidth = $(window).width();
var viewportHeight = window.innerHeight ? window.innerHeight : $(window).height(); // this is to work with Opera
zoomimg.css({'position': 'absolute', 'left': (viewportWidth/2)-(zoomimg.width()/2), 'top' : (viewportHeight/2)-(zoomimg.height()/2)}).draggable();
$(document).keydown(function(event) {
event = event || window.event;
var viewportWidth = $(window).width();
var viewportHeight = window.innerHeight ? window.innerHeight : $(window).height(); // this is to work with Opera
if (event.keyCode == 38) {
width = zoomimg.width();
height = zoomimg.height();
zoomimg.width(width*1.2).height(height*1.2);
var viewportWidth = $(window).width();
var viewportHeight = window.innerHeight ? window.innerHeight : $(window).height();
zoomimg.css({'left': (viewportWidth/2)-(zoomimg.width()/2), 'top' : (viewportHeight/2)-(zoomimg.height()/2)});
} else if (event.keyCode == 40) {
width = zoomimg.width();
height = zoomimg.height();
zoomimg.width(width*0.8).height(height*0.8);
var viewportWidth = $(window).width();
var viewportHeight = window.innerHeight ? window.innerHeight : $(window).height();
zoomimg.css({'left': (viewportWidth/2)-(zoomimg.width()/2), 'top' : (viewportHeight/2)-(zoomimg.height()/2)});
} else {
return
}
});
});
You should put an ID 'zoomimg' on the tag for it to work, and overflow:hidden on the #container . Also ditch that display:table and display:table-cell they're useless now that we center with Javascript. Also, pressing the down arrow key will cause the container to scroll down, so you should use other keys, as the arrows are reserved by the browser for scrolling the viewport.