Develop Reference

Bring element on top of modal backdrop

I am trying to build a guide functionality for my application. As a part of this functionality, it is expected that a tooltip is shown next to the target HTML element and this target element is brought on top of modal backdrop that appears together with the tooltip.
The problem is that after significant effort I still cannot make HTML element show on top of the modal backdrop. Simple tricks like z-index: 10000 !important; position: relative do not help. Also changing parent elements' z-index by disabling it in Firefox Developer Tools (and leaving z-index: 10000 !important; position: relative for the target element that is supposed to be on top of the modal backdrop) does not help.
HTML of the application is quite complex with many elements. But I want to be able to "highlight" any given element by bringing it on top of the modal overlay knowing only its id. Is there an easy way to do that with JavaScript/React?
Hopefully there is a way to do this without modifying the DOM, which would be highly preferable.
UPD: Code demo - press hat button to show guide/tooltips

Remove the z-index from .form-wrapper and apply relative position with z-index for the targetted elements.
I did this by adding
d.classList.add("tooltip-active-element");
to App.js#77
Also added the class to the css file:
.tooltip-active-element {
position: relative;
z-index: 2;
background: red;
}
and removed the z-index value from other classes, the key one being the .form-wrapper class.
Working demo: https://codesandbox.io/s/tooltip-z-index-forked-fg9pt

How to input a CSS class with JavaScript to affect another function

I have gone at a lot of informative sites in order to find answer but no luck so far. Thus now asking here.
CSS Class
.toppy {
:-webkit-full-screen {position: relative; top: -1310;}
:-moz-full-screen {position: relative; top: -1310;}
:-ms-fullscreen {position: relative; top: -1310;}
fullscreen {position: relative; top: -1310;}
}
JS Input
window.onscroll = function() {mss()};
function mss() {
var posi = document.body.scrollTop;
document.getElementById("toppy").style.top = -posi;
}
Depending on a position on a web page, this should give the value (posi). Negatived as CSS works on that way, and trying to update CSS with style(top) value (posi). However, no updating.
JS into which CSS influences
function FullScreen() { .... code .... }
CSS affects to this. If CSS has defined without class .toppy, function FullScreen works nicely opening full screen with the CSS's pre-set values (-1310) at the position downwards from the top.
But why is CSS's style property top not being updated by JS input function and therefore changing the position of the FullScreen to open at? My goal is to obtain the full screen to be opened at its current position on page. Some browsers do this automatically, some do not. Thus needing coding.
Or does one have to define a variable in css (e.g. var(--posi)) and proceed on this way but I do not have a real clue how to do that?
Many thanks for replies!
Update:
Thanks for the points. Valid ones. However, as the problem remains, I think the issue here is how to link a css to certain js being the case paricularry with this fullscreen. If I had two identical js fullscreen (expect function name), how would I define above kind of css to one js and another css to another js? As for me, it seems that css for fullscreen is (defined as above) not accepting any id or class tags, or I do not know how to link id to js? Syntaxing? Regards!

JQuery autocomplete appears behind JQuery menu

I have a JQuery autocomplete search box which when displaying the search results in the dropdown window appears behind a JQuery dropdown menu directly below it (see image). I have tried increasing the z-index value of everything I can find in the CSS for the autocomplete search but it still doesn't fix the problem. What else should I be trying?
Fiddle link: http://jsfiddle.net/tonyyeb/LKDBh/18/

Thanks for everyone's contributions. I have since found a solution given to me by a forum user:
The autocomplete wrapper is being given a z-index of 1 by the jQuery library (hard-coded), >whereas the menu (via CSS) has a z-index of 100; easiest solution is to use -
.ui-autocomplete {
z-index: 100 !important;
}

I had a similar issue with a website recently and I've fixed this with the following method:
Make sure that you position both elements absolute OR relative (z-index only works when you use the 'position' css element. So you should either use position: absolute; or postion: relative;. That totally depends on your code/css. When you don't use the position element right now, you should probably use the position: relative; element since the position:absolute; element will position the referring element absolutely which will probably screw up your layout).
Then make sure you give the dropdown a z-index which is lower then the z-index for the menu.
Example
.search-dropdown{
position: relative; or position: absolute;
z-index: 1;
}
.jquery-menu{
position: relative; or position: absolute;
z-index: 2;
}

Now, you've added
position: relative;
z-index: 1;
to .ui-widget.
Remove it there and add it directly to the dropdown's css which appears when you enter something in the input field (Chrome/Firefox: Right Click on the dropdown and inspect element to see its class/ID).
Hope this helps!

A few months ago I had a similar problem, and searched the web.
The solution was in the CSS styling.
I added an inline class (ui-front) to the element that holds the autocomplete input element.
Not sure it will solve your problem, but it's an easy experiment.
Best of luck!

Question has been posted long time ago. Still, i also have a solution that works and not listed till now .
just add this on top of your page and problem should be solved.
.pac-container { position: absolute; cursor: default;z-index:3000 !important;}

Media Queries not working properly after Javascript alters element CSS

any idea why in the example below, media queries stops changing the height of the menu bar after it's been changed by js? (make window small and click on the arrow to expand the mini menu). Do I need to register a point of origin for the menu element or something?
CSS:
#menu {
position: fixed;
left: 0px;
bottom: 0px;
width: 100%;
height: 90px;
z-index: 11000;
opacity: 1;
background-color: #F03600;
}
JS:
if ($("#arrowup").css('top') == '0px') {
$("#menu").animate({'height':'270px'}, 800, "easeInOutQuint");
} else {
$("#menu").animate({'height':'55px'}, 800, "easeInOutQuint");
}
You can check out the page here, all the code's on a single page:
http://www.nioute.co.uk/stuff/
Also, what's a good read with regards to media queries / js interaction?
Thanks!

The reason the media queries don't work is because when you modify the bar with Javascript, it applies inline-css. This overrides CSS that you may have in your stylesheets. The problem seems to be, when you toggle the arrow back down, #menu has an inline style of height="55px" applied to it, which blocks the regular style of 90px on a larger size.
The solution would be to clear the style when the window is resized to larger than your media query breakpoint using something like $(window).resize(function()...); and checking the current width of the window against your breakpoint. If it returns true, call $('#menu').attr('style', ''); and that will remove the inline style.

You can use class for adding some styles to elements and removing they after the job instead of getElementById(#menu).style.height = ...
for example:
getElementById(#menu).classList.add("newHeight")
Or
getElementById(#menu).classList.remove("newHeight")

Showing div at the center of the webpage

I have a div showing "Please wait". The markup for the div is
<div id="pleaseWait" class="divOuterPleaseWait" style="left:expression((documentElement.clientWidth-this.offsetWidth)/2);top:expression(documentElement.scrollTop+((documentElement.clientHeight-this.clientHeight)/2 ));">Please Wait...</div>
This is working fine with IE7. In IE7 the div is show at the center of the page. But excepted behariour is not optained in other browsers (ie. IE8,IE9,FireFox,Google Chrome etc). What should i give to get this working in all browsers? Also can I move the inline style to the my CSS?

A good way to center a div is to use fixed positioning, top and left set to 50% and left and top margin to the negative of half of the width/height:
http://jsfiddle.net/fLa4S/

See this SO answer, or this jsfiddle (press the 'confirm' button). The css you showed in your question is browser specific (especially: IE). In javascript you can center an element by determining the 'viewport' dimensions (height/width of the available screen) and position your element relative to those dimension. The links here demonstrate a way to do that.

It doesn't work in "other browsers" because you are using expressions in your CSS which are 1) incredibly bad for a variety of reasons (slow, deprecated, non-standard) and 2) unnecessary.
You can use pure CSS positioning (percentages and negative margins) or a little JavaScript (jQuery makes this very easy) to accomplish the same thing in all browsers.

Another approach:
<div style="text-align:center;width=200px;margin-left:auto;margin-right:auto">Please wait...</div>

CSS expressions are only working in IE. However, it´s generally not a good idea to use them because they are not W3C conform and in addition they can be very slow when you make heavy use of them.
The CSS attribute position: fixed could help you here:
#pleaseWait {
width: 400px;
height: 200px;
position: fixed; /* IE8+ */
left: 50%;
top: 50%;
margin-left: -200px; /* half of width*/
margin-top: -100px; /* half of height*/
}
If you have to still support <=IE7 you have to use JavaScript (but not within the CSS definition!)

Using auto as margins and defining a width and hight should be enough
<div style="width:200px;height:50px;margin:auto;text-align:center">Please wait ...</div>
If you only want to center verticaly, use margin: 0 auto;
PS: if you want to be more XHTML-correct, put your CSS in a CSS-file and use a class or a id to define the css-styling
I've answered this before: How to set the div in center of the page