CSS I want a div to be on top of everything

Question

In order for z-index to work, you'll need to give the element a position:absolute or a position:relative property. Once you do that, your links will function properly, though you may have to tweak your CSS a bit afterwards.

Yes, in order for the z-index to work, you'll need to give the element a position: absolute or a position: relative property... fine.

But... pay attention to parents!

The element's z-index may be limited by its parent's z-index value.

You have to go up the nodes of the elements to check if at the level of the common parent the first descendants have a defined z-index.

All other descendants can never be in the foreground if at the base there is a lower definite z-index.**

In this snippet example, div1-2-1 has a z-index of 1000 but is nevertheless under the div1-1-1 which has a z-index of 3.

This is because div1-1 has a z-index greater than div1-2.

.div {
  
}

#div1 {
  z-index: 1;
  position: absolute;
  width: 500px;
  height: 300px;
  border: 1px solid black;
}

#div1-1 {
  z-index: 2;
  position: absolute;
  left: 230px;
  width: 200px;
  height: 200px;
  top: 31px;
  background-color: indianred;
}

#div1-1-1 {
  z-index: 3;
  position: absolute;
  top: 50px;
  width: 100px;
  height: 100px;
  background-color: burlywood;
}

#div1-2 {
  z-index: 1;
  position: absolute;
  width: 200px;
  height: 200px;
  left: 80px;
  top: 5px;
  background-color: red;
}

#div1-2-1 {
  z-index: 1000;
  position: absolute;
  left: 70px;
  width: 120px;
  height: 100px;
  top: 10px;
  color: red;
  background-color: lightyellow;
}

.blink {
  animation: blinker 1s linear infinite;
}

@keyframes blinker {
  50% {
    opacity: 0;
  }
}

.rotate {
  writing-mode: vertical-rl;
  padding-left: 50px;
  font-weight: bold;
  font-size: 20px;
}

<div class="div" id="div1">div1</br>z-index: 1
  <div class="div" id="div1-1">div1-1</br>z-index: 2
    <div class="div" id="div1-1-1">div1-1-1</br>z-index: 3</div>
  </div>
  
  <div class="div" id="div1-2">div1-2</br>z-index: 1</br><span class='rotate blink'><=</span>
    <div class="div" id="div1-2-1"><span class='blink'>z-index: 1000!!</span></br>div1-2-1</br><span class='blink'> because =></br>(same</br>   parent)</span></div>
  </div>
</div>

For z-index:1000 to have an effect you need a non-static positioning scheme.

Add position:relative; to a rule selecting the element you want to be on top

You need to add position:relative; to the menu. Z-index only works when you have a non static positioning scheme.

z-index property enables you to take your control at front. the bigger number you set the upper your element you get.

position property should be relative because position of html-element should be position relatively against other controls in all dimensions.

element.style {
   position:relative;
   z-index:1000; //change your number as per elements lies on your page.
}

I gonna assumed you making a popup with code from WW3 school, correct? check it css. the .modal one, there're already word z-index there. just change from 1 to 100.

.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}