Consider:
$("#PlotPlace").append('<div style="position:absolute;left:200px;top:40px;font-size:smaller">Hello world!</div>');
I need to execute that line only if the width of the resultant text would be less than 60px. How can I check the width before placing the object?
Unfortunately, the div will only have a width value once it is rendered into the DOM.
I would append that content to an inconspicuous area of the document, perhaps even absolutely positioned so that no flow disruption occurs, and make sure that it is set to "visibility:hidden". That way it will be inserted into the DOM and be rendered, but be invisible to the viewer.
You can then check the width on it, and move it into position and set it to "visibility:visible" at that point. Otherwise, you can remove it from the document.
Maybe you can append it invisible, then check it's width, and then consider to show or hide.
$("#PlotPlace").append('<div style="position:absolute;left:9001px;top:40px;font-size:smaller">Hello world!</div>');
var div = $('#PlotPlace').children("div");
if(div.width() < 60)
div.css({left:200})
Sounds like something you'd have to hack. I don't believe the JavaScript runtime in any browser has an event you can hook into in between calculating the layout and displaying the element, so you can add it in a way that it can't be seen and doesn't affect the height (doesn't cause additional scrolling), and then show/hide it based on the width at this point. It's hacky and ugly, but because you don't have many event hooks it might be the only way to do it.
You can´t. At least not so easy. The text you insert is written in a specific font, which must be rendered by the browser, then you know the width of the element. By the Way, what exactly do you want to insert, with such a restriction? Wouldn´t it be simpler to cut the text within the output parameters?
Related
I'm creating some HTML elements dynamically via JavaScript. Something line this:
var author = document.createElement("div");
author.innerHTML = _feed[i].author;
author.className = "author";
The browser returns offsetHeight = 0 if the element is not added to the document yet.
I want to know the element's height before appending them to the document because if the element's resulting height is too big I need to take some actions (make it smaller), and only after that add it to the document.
My suggestion is to add it to the page with a left margin of -10000 or something, so that it's not visible. Then you can get the dimensions, do what you need, and then change the left margin so that it's where you want it. This is assuming you would use absolute positioning.
But so far as I know, the browser will not report that information on elements not in the DOM.
Dan the problem you are going to have is that unless you add it to the DOM then you can never accurately know what the height will be. The reason for this is that as the element is not in the DOM, it cannot be affected by styles set in CSS or the browsers default styles. Even if the element itself has no specific styles applied to it then its parent element may do, or even its grandparent element (did I just make grandparent element up?).
The only accurate way of getting the height is to place the element exactly where it will sit in the DOM and then detect the height. I don't think visibility:hidden; will work as its presence will still be felt by elements around it (pushing margins around and positioning of other elements).
How about position:absolute; left: -5000px;? That may work.
How can I get the height at which an element was rendered, after I have changed it's height?
E.g. the text make a very long (high) div, then I shorten it to make it look neat and I use overflow:hidden to temporarily cut off excess text. Now, dynamically, I want to resize the div to be as high as it would have been if I never touched it.
How is this possible to do?
CSS & JQuery is welcome.
Thanks
Grab that value prior to the re-size.
You can then save it, and use it, in two different ways:
// grab it as a JS value and keep it stored somewhere
var originalHeight = element.height();
// grab and store the original value in the rel HTML attribute
el.attr("rel", el.height()
Have you noticed that by using jquery's slideDown(), even on elements with dynamic content, you always get the perfect height of the effected element. Which is, for me at least, impossible to do by simply animating the css height value. Mostly because there is no way for me to know how did the height of an element (with a display:none) changed, during a dynamic content (AJAX) update.
And since i've been working on some custom controls, i do need that capability to calculate things the way slideDown() does.
If you are inserting a new dinamically loaded content, it means you have that element in memory, so you can refer to it and know its height. You only have to read its height (or maybe outerHeight) and slide by that amount.
EDIT
Just give a height of 0 to the hiden item and overflow:hidden, so that the content inside it won't be sohwn, and it will retain its height.
http://jsfiddle.net/jgyLm/9/
You can try this after appending the dynamic content to the element.
$(element).height();
$(element).outerHeight();//if you need margin to be included pass true to outerHeight method
This is a follow up question to How can I stop an IFrame reloading when I change it's position in the DOM? if you want the background.
I have an inline div <div id="leaderboard-slot"></div> (with a fixed width and height) and another div ("leaderboard-loader") further down the page with the actual content for that div.
For various reasons (see previous thread), I am unable to simply do an appendChild or similar.
Instead, I'm hoping to position leaderboard-loader such that it takes up the space "reserved" by leaderboard slot. I've used some jQuery methods to do this:
var loader = $('leaderboard-loader');
var dest = $('leaderboard-slot');
var pos = dest.getPosition();
loader.setStyle('top', pos.y + 'px');
loader.setStyle('left', pos.x + 'px');
which I fire on document load and resize. However, if other elements within the page cause a reflow, then the target div moves, but the loader doesn't.
Is there a safe way of doing this - it needs to work when I know nothing else about the page (ie I can't just make this call on any other methods that might cause a reflow, because I don't know what those are).
Any help would be much appreciated - thank you :)
If I understand your question correctly, there is no need for Javascript. Just put leaderboard-loader in front of the leaderboard-slot tag, give it position: absolute and identical width and height. If slot is a normal element, loader will float above it and cover it perfectly.
<div id="leaderboard-loader"></div><div id="leaderboard-slot"></div>
I'm starting to regret my answer now. Hopefully you can find something better than the absolute positioning workaround. But, in the spirit of kludgey solutions, you could call the repositioning script on a timer. sigh.
You could put them both in the same relative positioned, 0 margin div, with the temporary div z-indexed on top of the slow loader.
Make them both absoluely positioned in the parent, not the window, at 0:0 and the same size.
You can use opacity and fade one in as you fade the other one out, or just swap visibility:hidden and visible for the two elements when you are ready..
I am currently trying to modify a Javascript function that "slides in" a <div>. The script as it is requires you to define the height of the div, so it is mostly useless in dynamically filled <div>s. I found some text on the clientHeight property in javascript, but it would appear that it doesn't support <div>s with display set to none (which is the method used to slide the div in). That makes sense, as the height of that div in the client window is nothing.
Basically I was wondering what other methods you all know of, or if there's a way to get around the clientHeight = 0 when display: none.
Thanks!
Oh, and here's the function I'm using:
function getDivHeight(objName) {
return boxHeight = document.getElementById(objName).clientHeight;
}
A simple solution is to set it's visibility to "hidden" and it's display to "block" and measure it. However, some modern browsers will manage to update the page layout during this short time and you will get a nasty flicker. The easiest way to overcome this is to place the element in an absolutely positioned container with overflow set to "hidden".
I've had luck cloning the element, moving it offscreen, then displaying it to get the client height:
var original = document.getElementById(some_id);
var new_item = original.cloneNode(true);
document.body.appendChild(new_item); // item already hidden, so it won't show yet.
// you may wish to validate it is hidden first
new_item.style.position = "absolute";
new_item.style.left = "-1000px";
new_item.style.display = "block";
var height = new_item.clientHeight;
EDIT: Looking through the jQuery code, they do exactly what Tsvetomir Tsonev suggests. jQuery temporarily sets the style to "display: block; position: absolute; visibility: none", and then measures the height, swapping the properties back after the measurement.
So, it looks like you're stuck with having to do something hackish, whether it's cloning the node or risking having it flicker in some browsers... I like Tsvetomir's suggestion better than my initial hack as it, at least, doesn't involve cloning a node into the DOM that you don't need. Either way, the element must not be set to "display: none" in order to measure it's height. Isn't the DOM wonderful? :-)
EDIT 2: Also worth noting that, after jQuery gathers the height, it adds allowances for padding, margin and border sizes, so you may need to as well.
Yes, an element that is not displayed on the page has no dimensions.
It kind of makes sense. Consider an element that has been created and filled with a bunch of text, but not yet added to the document tree. How high is it? Depends on font-size. How big is font-size? Depends where in the document that div is inserted; its parent font-size would inherit through.
Similarly for an element with “display: none”. It's not rendered, so it has no dimensions. Couldn't we ask “how high would this be if it were ‘display: block’”? Turns out no, because if it were displayed, that in itself could change the dimensions of its parent block, and then the dimension of displayed elements would be inconsistent with the dimensions of non-displayed elements!
The typical solution is to unset “display: none”, measure the height of the element, and then immediately re-set “display: none”. The browser won't redraw in the middle of a bit of JavaScript, so you won't see a flicker on the page.
I nkow you guys solved this a long time ago but I thought I should share this since it quite tricky to get the height of a hidden div tag.
heres what I did after reading your post,
I placed the div i want to slide inside a 1px height div with overflow set to hidden.
you dont even need to set the display of the inner div to none since it is already there and if you use offsetHeight it should return the proper height for all browsers and you can use that height to slide your div up an down.
PEACE!!!
In IE you could try scrollHeight, but I'm not sure if it will work or if it is cross browser.