最简单的方法是在包含元素上设置position: relative，在容器内的工具提示元素上设置position: absolute，使其相对于父元素(包含元素)浮动。例如:

<div style="background: yellow;">
    <div style="display: inline-block; position: relative; background: pink;">
        <label>Name</label>
        <input type="text" />

        <div style="background: #e5e5e5; position: absolute; top: -10px; left: 0; right: 0;">
            Tooltip text
        </div>
    </div>
</div>

这是一个纯css3实现(可选JS)

你要做的唯一一件事就是在任何div上设置一个名为“data-tooltip”的属性，当你将鼠标悬停在它上面时，该文本将显示在它旁边。

我已经包含了一些可选的JavaScript，可以使工具提示显示在光标附近。如果您不需要这个特性，您可以放心地忽略这个小提琴的JavaScript部分。

如果您不希望在悬停状态上淡入，只需删除过渡属性。

它的样式类似于title属性工具提示。这是JSFiddle: http://jsfiddle.net/toe0hcyn/1/

HTML的例子:

<div data-tooltip="your tooltip message"></div>

CSS:

*[data-tooltip] {
    position: relative;
}

*[data-tooltip]::after {
    content: attr(data-tooltip);

    position: absolute;
    top: -20px;
    right: -20px;
    width: 150px;

    pointer-events: none;
    opacity: 0;
    -webkit-transition: opacity .15s ease-in-out;
    -moz-transition: opacity .15s ease-in-out;
    -ms-transition: opacity .15s ease-in-out;
    -o-transition: opacity .15s ease-in-out;
    transition: opacity .15s ease-in-out;

    display: block;
    font-size: 12px;
    line-height: 16px;
    background: #fefdcd;
    padding: 2px 2px;
    border: 1px solid #c0c0c0;
    box-shadow: 2px 4px 5px rgba(0, 0, 0, 0.4);
}

*[data-tooltip]:hover::after {
    opacity: 1;
}

基于鼠标位置的工具提示位置更改的可选JavaScript:

var style = document.createElement('style');
document.head.appendChild(style);

var matchingElements = [];
var allElements = document.getElementsByTagName('*');
for (var i = 0, n = allElements.length; i < n; i++) {
    var attr = allElements[i].getAttribute('data-tooltip');
    if (attr) {
        allElements[i].addEventListener('mouseover', hoverEvent);
    }
}

function hoverEvent(event) {
    event.preventDefault();
    x = event.x - this.offsetLeft;
    y = event.y - this.offsetTop;

    // Make it hang below the cursor a bit.
    y += 10;

    style.innerHTML = '*[data-tooltip]::after { left: ' + x + 'px; top: ' + y + 'px  }'

}

我为它创造了一个公式。 首先是html

<div class="tooltip-container">
  <button class="tooltip-tarjet">
    My Button
  </button>
  <div class="tooltip-element"> 
    This is my tooltip content right here...
  </div>
</div>

现在是它的css

.tooltip-container { 
  /* it contains the tooltip message and the one firing the tooltip
   * it has position relative since it allows for a better responsive positioning
   * of the tooltip-element */
  display: inline-block;
  position: relative;
  flex-direction: row;
}
.tooltip-tarjet:hover + .tooltip-element {
  /* this selector rule matches the tooltip-element right after
   * tooltip-tarjet at a hover action
   *  */
  display: inline-block;
  position: absolute;
  background-color: #869096;
  color: white;
  opacity: 1;
  transition: all 1s;
}
.tooltip-element { 
  /* here goes the tooltip-element styles and positioning, now your
   * tooltip element will always remain to your desired positionno matter
   * the screen size at hand 
   *  */ 
  display: none; 
  opacity: 0;
  text-align: center;
  padding: 7px;
  z-index: 10;
  width: 200px;
  left: -60px;
  bottom: 48px;
  border-radius: 5px;
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  font-size: 12px;
  line-height: 1.5;
}

你可以像这样在onmouseover和onmouseout期间切换子div:

function Tooltip(el, text) {
  el.onmouseover = function() {
    el.innerHTML += '<div class="tooltip">' + text + '</div>' 
    }
  el.onmouseout = function() {
    el.removeChild(el.querySelector(".tooltip"))
  }
}

//Sample Usage
Tooltip(document.getElementById("mydiv"),"hello im a tip div")

Stack Snippets & jsFiddle中的例子

function Tooltip(el, text) { el.onmouseover = function() { el.innerHTML += '<div class="tooltip">' + text + '</div>' } el.onmouseout = function() { el.removeChild(el.querySelector(".tooltip")) } } //Sample Usage Tooltip(document.getElementById("mydiv"), "I'm a tooltip") #mydiv { position: relative; display: flex; align-items: center; justify-content: center; width: 120px; height: 50px; padding: 5px 10px; background-color: #e2f7ff; box-shadow: 1px 1px 1px 0px #cecece; } .tooltip { position: absolute; display: inline-block; white-space: nowrap; width: auto; height: auto; background-color: #11121b; color: white; padding: 4px 6px; border-radius: 3px; z-index: 99; left: 100%; top: 0; } <div id="mydiv"> This is just a div </div>

这个问题有很多答案，但它仍然可能会帮助到一些人。它适用于所有左、右、上、下位置。

下面是css:

    .m-tb-5 {
        margin-top: 2px;
        margin-bottom: 2px;
    }
    [data-tooltip] {
        display: inline-block;
        position: relative;
        cursor: help;
        padding: 3px;
    }
    /* Tooltip styling */
    [data-tooltip]:before {
        content: attr(data-tooltip);
        display: none;
        position: absolute;
        background: #000;
        color: #fff;
        padding: 3px 6px;
        font-size: 10px;
        line-height: 1.4;
        min-width: 100px;
        text-align: center;
        border-radius: 4px;
    }
    /* Dynamic horizontal centering */
    [data-tooltip-position="top"]:before,
    [data-tooltip-position="bottom"]:before {
        left: 50%;
        -ms-transform: translateX(-50%);
        -moz-transform: translateX(-50%);
        -webkit-transform: translateX(-50%);
        transform: translateX(-50%);
    }
    /* Dynamic vertical centering */
    [data-tooltip-position="right"]:before,
    [data-tooltip-position="left"]:before {
        top: 50%;
        -ms-transform: translateY(-50%);
        -moz-transform: translateY(-50%);
        -webkit-transform: translateY(-50%);
        transform: translateY(-50%);
    }
    [data-tooltip-position="top"]:before {
        bottom: 100%;
        margin-bottom: 6px;
    }
    [data-tooltip-position="right"]:before {
        left: 100%;
        margin-left: 6px;
    }
    [data-tooltip-position="bottom"]:before {
        top: 100%;
        margin-top: 6px;
    }
    [data-tooltip-position="left"]:before {
        right: 100%;
        margin-right: 6px;
    }

    /* Tooltip arrow styling/placement */
    [data-tooltip]:after {
        content: '';
        display: none;
        position: absolute;
        width: 0;
        height: 0;
        border-color: transparent;
        border-style: solid;
    }
    /* Dynamic horizontal centering for the tooltip */
    [data-tooltip-position="top"]:after,
    [data-tooltip-position="bottom"]:after {
        left: 50%;
        margin-left: -6px;
    }
    /* Dynamic vertical centering for the tooltip */
    [data-tooltip-position="right"]:after,
    [data-tooltip-position="left"]:after {
        top: 50%;
        margin-top: -6px;
    }
    [data-tooltip-position="top"]:after {
        bottom: 100%;
        border-width: 6px 6px 0;
        border-top-color: #000;
    }
    [data-tooltip-position="right"]:after {
        left: 100%;
        border-width: 6px 6px 6px 0;
        border-right-color: #000;
    }

    [data-tooltip-position="left"]:after {
        right: 100%;
        border-width: 6px 0 6px 6px;
        border-left-color: #000;
    }
    /* Show the tooltip when hovering */
    [data-tooltip]:hover:before,
    [data-tooltip]:hover:after {
        display: block;
        z-index: 50;
    }

HTML标签可以是这样的:

<p data-tooltip-position="right" data-tooltip="Some tooltip text here" title=" > text here </p> .

<p data-tooltip-position="left" data-tooltip="Some tooltip text here" title=" > text here </p> .

<p data-tooltip-position="top" data-tooltip="Some tooltip text here" title=" > text here </p> .

<p data-tooltip-position="bottom" data-tooltip="Some tooltip text here" title=" > text here </p> .

我的版本是

.tooltip{
display: inline;
position: relative; /** very important set to relative*/
}

.tooltip:hover:after{
background: #333;
background: rgba(0,0,0,.8);
border-radius: 5px;
bottom: 26px;
color: #fff;
content: attr(title); /**extract the content from the title */
left: 20%;
padding: 5px 15px;
position: absolute;
z-index: 98;
width: 220px;
}

.tooltip:hover:before{
border: solid;
border-color: #333 transparent;
border-width: 6px 6px 0 6px;
bottom: 20px;
content: "";
left: 50%;
position: absolute;
z-index: 99;
}

然后是HTML

<div title="This is some information for our tooltip." class="tooltip">bar </div>