javascript - 什么是 offsetHeight、clientHeight、scrollHeight？

Question

想解释一下offsetHeight、clientHeight和scrollHeight或offsetWidth、有什么区别clientWidth 和 scrollWidth?

在客户端工作之前，必须知道这种差异。否则他们一半的生命将花在修复 UI 上。

Fiddle , 或内联:

function whatis(propType) {
  var mainDiv = document.getElementById("MainDIV");
  if (window.sampleDiv == null) {
    var div = document.createElement("div");
    window.sampleDiv = div;
  }
  div = window.sampleDiv;
  var propTypeWidth = propType.toLowerCase() + "Width";
  var propTypeHeight = propType + "Height";

  var computedStyle = window.getComputedStyle(mainDiv, null);
  var borderLeftWidth = computedStyle.getPropertyValue("border-left-width");
  var borderTopWidth = computedStyle.getPropertyValue("border-top-width");

  div.style.position = "absolute";
  div.style.left = mainDiv.offsetLeft + Math.round(parseFloat((propType == "client") ? borderLeftWidth : 0)) + "px";
  div.style.top = mainDiv.offsetTop + Math.round(parseFloat((propType == "client") ? borderTopWidth : 0)) + "px";
  div.style.height = mainDiv[propTypeHeight] + "px";
  div.style.lineHeight = mainDiv[propTypeHeight] + "px";
  div.style.width = mainDiv[propTypeWidth] + "px";
  div.style.textAlign = "center";
  div.innerHTML = propTypeWidth + " X " + propTypeHeight + "( " +
    mainDiv[propTypeWidth] + " x " + mainDiv[propTypeHeight] + " )";



  div.style.background = "rgba(0,0,255,0.5)";
  document.body.appendChild(div);

}
document.getElementById("offset").onclick = function() {
  whatis('offset');
}
document.getElementById("client").onclick = function() {
  whatis('client');
}
document.getElementById("scroll").onclick = function() {
  whatis('scroll');
}

#MainDIV {
  border: 5px solid red;
}

<button id="offset">offsetHeight & offsetWidth</button>
<button id="client">clientHeight & clientWidth</button>
<button id="scroll">scrollHeight & scrollWidth</button>

<div id="MainDIV" style="margin:auto; height:200px; width:400px; overflow:auto;">
  <div style="height:400px; width:500px; overflow:hidden;">

  </div>
</div>

Answer 1

要知道区别，您必须了解 box model ，但基本上:

clientHeight :

returns the inner height of an element in pixels, including padding but not the horizontal scrollbar height, border, or margin

offsetHeight :

is a measurement which includes the element borders, the element vertical padding, the element horizontal scrollbar (if present, if rendered) and the element CSS height.

scrollHeight :

is a measurement of the height of an element's content including content not visible on the screen due to overflow

---

我会让事情变得更容易:

考虑:

<element>                                     
    <!-- *content*: child nodes: -->        | content
    A child node as text node               | of
    <div id="another_child_node"></div>     | the
    ... and I am the 4th child node         | element
</element>                                    

scrollHeight:整个内容和填充(可见或不可见)
_{所有内容的高度+填充，尽管元素的高度。}

clientHeight:可见的内容和填充
_{仅可见高度:内容部分受明确定义的元素高度限制。}

offsetHeight:VISIBLE content & padding +边框+滚动条
_{元素在文档中所占的高度。}