Plain JavaScript tooltip

I am trying to make a tooltip in plain JavaScript which is shown on hover. Like the one in Stack Overflow on hover over the profile name a div is shown.

I tried using onmouseover , onmouseout and added setTimeout to give the user a few seconds to move mouse over the tooltip content. But it was not working as I thought.

I really like pure JavaScript more than using any libraries. Can some one help me out?

This is what I did in pure JavaScript.

HTML

<div class = "name" onmouseover="show()" onmouseout="hide()">
    NAME
        <div class = "tooltip">
            PROFILE DETAILS
        </div>
    </div>

    <div class = "name" onmouseover="show()" onmouseout="hide()">
    NAME 2
        <div class = "tooltip" >
            PROFILE DETAILS 2
        </div>
    </div>

    <div class = "name" onmouseover="show()" onmouseout="hide()">
    NAME 3
        <div class = "tooltip" >
            PROFILE DETAILS 3
        </div>
    </div>

CSS

.name{
        float:left;
        margin:100px;
        border:1px solid black;
    }
    .tooltip{
        position:absolute;
        margin:5px;
        width:200px;
        height:100px;
        border:1px solid black;
        display:none;
    }

JavaScript

var name = document.getElementsByclassName("name");
    var tp = document.getElementsByclassName("tooltip");

    function show(){
        tp.style.display="block";
    }
    function hide(){
        tp.style.display="";
    }

Solution with no JavaScript

This uses CSS pseudo hover to set the display of the hidden element. The display none needs to be in the style and not on the element so it can be overwritten in the hover.

.couponcode:hover .coupontooltip {
  /* NEW */
  display: block;
}

.coupontooltip {
  display: none;
  /* NEW */
  background: #C8C8C8;
  margin-left: 28px;
  padding: 10px;
  position: absolute;
  z-index: 1000;
  width: 200px;
  height: 100px;
}

.couponcode {
  margin: 100px;
}

<div class="couponcode">First Link
  <span class="coupontooltip">Content 1</span>
  <!-- UPDATED -->
</div>

<div class="couponcode">Second Link
  <span class="coupontooltip"> Content 2</span>
  <!-- UPDATED -->
</div>

External Link

Follow-Up:

If you need to support really old browsers, you would need to add a class to the outside element when the mouse enters the div. And remove that class when mouse leaves.

EDIT

Your code did not work because what is tp? Is a collection of elements and you are treating it as one. What you would need to do is pass in the reference to the element

HTML:

<div class = "name" onmouseover="show(this)" onmouseout="hide(this)">  <!-- added "this" 2 times -->

**JavaScript:

//var name = document.getElementsByclassName("name");  /* not needed */
//    var tp = document.getElementsByclassName("tooltip"); /* not needed */


function show (elem) {  /* added argument */
    elem.style.display="block"; /* changed variable to argument */
}
function hide (elem) { /* added argument */
    elem.style.display="";  /* changed variable to argument */
}

For non-customized tooltip, you can just add the message you want to display in tooltip in the title attribute of the main div. Just like this:

<div class = "name" onmouseover="show()" onmouseout="hide()" title="PROFILE DETAILS">

Then there is no need to add the onmouseover and onmouseout event handlers.

Fix for the original code

I was looking for something like this, and I came across this page. It helped me, but I had to fix your code, for it to work. I think that this is what you tried. You have to reference your objects by their "ID". Here is what I've done, and it works:

function show(elem) {
  elem.style.display = "block";
}

function hide(elem) {
  elem.style.display = "";
}

.name {
  float: left;
  margin: 100px;
  border: 1px solid black;
}

.tooltip {
  position: absolute;
  margin: 5px;
  width: 200px;
  height: 50px;
  border: 1px solid black;
  display: none;
}

<div class="name" onmouseover="show(tooltip1)" onmouseout="hide(tooltip1)">
  NAME
  <div class="tooltip" id="tooltip1">
    PROFILE DETAILS
  </div>
</div>

<div class="name" onmouseover="show(tooltip2)" onmouseout="hide(tooltip2)">
  NAME 2
  <div class="tooltip" id="tooltip2">
    PROFILE DETAILS 2
  </div>
</div>

<div class="name" onmouseover="show(tooltip3)" onmouseout="hide(tooltip3)">
  NAME 3
  <div class="tooltip" id="tooltip3">
    PROFILE DETAILS 3
  </div>
</div>

External link

The question said:

Plain JavaScript tooltip

But I think in modern times we can use vanilla JS and CSS. Specially, when we want o provide a good looking style it is a must.

This example is a simple implementation of pure JS and CSS.

Let's create a tooltip using CSS and add modify the behavior using JS. For this example, we will define a tip attribute to storage the text that will be shown on the tooltip.

visibility: hidden; and opacity: 0; will maintain the .tooltip hidden and will appear when [tip]:hover. Also, we can reposition the point of emission from the tooltip will be shown using style.transform.

Array.from(document.querySelectorAll('[tip]')).forEach(el => {
  let tip = document.createElement('div');
  tip.classList.add('tooltip');
  tip.innerText = el.getAttribute('tip');
  tip.style.transform =
    'translate(' +
      (el.hasAttribute('tip-left') ? 'calc(-100% - 5px)' : '15px') + ', ' +
      (el.hasAttribute('tip-top') ? '-100%' : '0') +
    ')';
  el.appendChild(tip);
  el.onmousemove = e => {
    tip.style.left = e.clientX + 'px'
    tip.style.top = e.clientY + 'px';
  };
});

[tip] .tooltip {
  position: fixed;
  font-size: 16px;
  line-height: 20px;
  padding: 5px;
  background: white;
  border: 1px solid #ccc;
  visibility: hidden;
  opacity: 0;
  box-shadow: -2px 2px 5px rgba(0, 0, 0, 0.2);
  transition: opacity 0.3s, visibility 0s;
}

[tip]:hover .tooltip {
  visibility: visible;
  opacity: 1;
}

button {
  display: block;
  cursor: pointer;
  padding: 8px 15px;
  border: 1px solid gray;
  border-radius: 4px;
  margin: 50px;
  font-size: 18px;
  background: white;
}

button:hover {
  border-color: dodgerblue;
}

<button tip="Click Me!">
  I have a tooltip
</button>
<button tip="Click Me Aswell!" tip-top tip-left>
  Top-left tooltip
</button>