ZH奶酪：HTML元素文本溢出显示省略号(...)

一 单行文本

overflow: hidden;
text-overflow: ellipsis;
white-space: nowrap;

overflow 属性规定当内容溢出元素框时发生的事情。

visible	默认值。内容不会被修剪，会呈现在元素框之外。
hidden	内容会被修剪，并且其余内容是不可见的。
scroll	内容会被修剪，但是浏览器会显示滚动条以便查看其余的内容。
auto	如果内容被修剪，则浏览器会显示滚动条以便查看其余的内容。
inherit	规定应该从父元素继承 overflow 属性的值。

　　

text-overflow 属性规定当文本溢出包含元素时发生的事情。

clip：修剪文本；

ellipsis：显示省略号来代表被修剪的文本；

string：使用给定的字符串来代表被修剪的文本；

white-space 属性设置如何处理元素内的空白。

normal	默认。空白会被浏览器忽略。
pre	空白会被浏览器保留。其行为方式类似 HTML 中的 <pre> 标签。
nowrap	文本不会换行，文本会在在同一行上继续，直到遇到 <br> 标签为止。
pre-wrap	保留空白符序列，但是正常地进行换行。
pre-line	合并空白符序列，但是保留换行符。
inherit	规定应该从父元素继承 white-space 属性的值。

二 多行文本，提供了几种方法，效果图中的每一段文字对应一个方法：

// https://github.com/josephschmitt/Clamp.js var module = document.getElementById("clampjs");
$clamp(module, {clamp: 2});

// https://github.com/ftlabs/ftellipsis var element = document.getElementById('ftellipsis');
var ellipsis = new Ellipsis(element);

ellipsis.calc();
ellipsis.set();

// http://codepen.io/Merri/pen/Dsuim /**
* TextOverflowClamp.js
*
* Updated 2013-05-09 to remove jQuery dependancy.
* But be careful with webfonts!
*/

// bind function support for older browsers without it
// https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/bind if (!Function.prototype.bind) {
Function.prototype.bind = function (oThis) {
if (typeof this !== "function") {
// closest thing possible to the ECMAScript 5 internal IsCallable function
throw new TypeError("Function.prototype.bind - what is trying to be bound is not callable");
}

var aArgs = Array.prototype.slice.call(arguments, 1),
fToBind = this,
fNOP = function () {},
fBound = function () {
return fToBind.apply(this instanceof fNOP && oThis
? this
: oThis,
aArgs.concat(Array.prototype.slice.call(arguments)));
};

fNOP.prototype = this.prototype;
fBound.prototype = new fNOP();

return fBound;
};
}

// the actual meat is here
(function(w, d){
var clamp, measure, text, lineWidth,
lineStart, lineCount, wordStart,
line, lineText, wasNewLine,
ce = d.createElement.bind(d),
ctn = d.createTextNode.bind(d);

// measurement element is made a child of the clamped element to get it's style
measure = ce('span');

(function(s){
s.position = 'absolute'; // prevent page reflow
s.whiteSpace = 'pre'; // cross-browser width results
s.visibility = 'hidden'; // prevent drawing
})(measure.style);

clamp = function (el, lineClamp) {
// make sure the element belongs to the document
if(!el.ownerDocument || !el.ownerDocument === d) return;
// reset to safe starting values
lineStart = wordStart = 0;
lineCount = 1;
wasNewLine = false;
lineWidth = el.clientWidth;
// get all the text, remove any line changes
text = (el.textContent || el.innerText).replace(/\n/g, ' ');
// remove all content
while(el.firstChild !== null)
el.removeChild(el.firstChild);
// add measurement element within so it inherits styles
el.appendChild(measure);
// http://ejohn.org/blog/search-and-dont-replace/ text.replace(/ /g, function(m, pos) {
// ignore any further processing if we have total lines
if(lineCount === lineClamp) return;
// create a text node and place it in the measurement element
measure.appendChild(ctn(text.substr(lineStart, pos - lineStart)));
// have we exceeded allowed line width?
if(lineWidth < measure.clientWidth) {
if(wasNewLine) {
// we have a long word so it gets a line of it's own
lineText = text.substr(lineStart, pos + 1 - lineStart);
// next line start position
lineStart = pos + 1;
} else {
// grab the text until this word
lineText = text.substr(lineStart, wordStart - lineStart);
// next line start position
lineStart = wordStart;
}
// create a line element
line = ce('span');
// add text to the line element
line.appendChild(ctn(lineText));
// add the line element to the container
el.appendChild(line);
// yes, we created a new line
wasNewLine = true;
lineCount++;
} else {
// did not create a new line
wasNewLine = false;
}
// remember last word start position
wordStart = pos + 1;
// clear measurement element
measure.removeChild(measure.firstChild);
});
// remove the measurement element from the container
el.removeChild(measure);
// create the last line element
line = ce('span');
// give styles required for text-overflow to kick in
(function(s){
s.display = 'inline-block';
s.overflow = 'hidden';
s.textOverflow = 'ellipsis';
s.whiteSpace = 'nowrap';
s.width = '100%';
})(line.style);
// add all remaining text to the line element
line.appendChild(ctn(text.substr(lineStart)));
// add the line element to the container
el.appendChild(line);
}
w.clamp = clamp;
})(window, document);

// the only bit of jQuery
$(window).bind('load', function() {
clamp(document.getElementById('textoverflowclamp'), 3);
});

View Code
其中

（1）-webkit-line-clamp 这种方法指支持部分浏览器，而且要与其他两个属性同时使用：

.line-clamp {
display: -webkit-box;
-webkit-line-clamp: 3;
-webkit-box-orient: vertical;
}



（2）clamp.js 下载地址及使用方法：https://github.com/josephschmitt/Clamp.js

（3）ftellipsis 下载地址及使用方法：https://github.com/ftlabs/ftellipsis

（4）jQuery.dotdotdot 下载地址及使用方法：https://github.com/BeSite/jQuery.dotdotdot

参考文章：

[1] https://css-tricks.com/line-clampin/

[2] http://www.css88.com/archives/5206

[3] http://codepen.io/Merri/pen/Dsuim

[4] http://codepen.io/feiwen8772/pen/AckqK