如何在文本中间显示文本溢出省略号

如下，尽管这当然依赖于JavaScript：

function centralEllipsis(opts) {
    // the default settings, which can be overridden
    // by the user:
    var settings = {
        // the number of the original characters to show:
        'maxLength': 7,
        // the character-sequence, or HTML character-
        // entity to use to replace the missing characters:
        'ellipsis': '…',
        // the attribute to which you'd like to write the
        // original text (this function does also write
        // the text to the 'title' attribute though):
        'writeToAttribute': 'data-originaltext'
    },
   // the element upon which we're working (cached
   // because we'll access it more than once):
    _this = this;
    // iterating over the properties supplied by the user:
    for (var prop in opts) {
        // if the current property ('prop') of the object
        // ('opts') is enumerable and not from the prototype:
        if (opts.hasOwnProperty(prop)) {
            // we update that property in the settings object
            // (if the typeof the property-value ('opts[prop]')
            // is not equal to the string 'undefined', if it is
            // then we use the original property-value:
            settings[prop] = 'undefined' !== typeof opts[prop] ? opts[prop] : settings[prop];
        }
    }
    // we divide the settings.maxLength by 2 to work out
    // how many characters should appear at the beginning
    // of the string; using Math.ceil() to ensure whole
    // numbers:
    var prefixLength = Math.ceil(settings.maxLength / 2),
        // finding the length of the suffix by subtraction
        // of the prefixLength from the settings.maxLength:
        suffixLength = settings.maxLength - prefixLength,
        // setting the textContent of the current element
        // as the element's title text and storing it in
        // a variable:
        originalText = _this.title = _this.textContent,
        // empty variables initialised for later:
        prefix, suffix;
    // if the maxLength is less than the length of the original
    // text, then we go ahead (if not, we do nothing):
    if (settings.maxLength < originalText.length) {
        // storing the original text in the specified attribute:    
        _this.setAttribute(settings.writeToAttribute, originalText);
        // the prefix is the substring of the originalText, for
        // settings.maxLength number of characters starting at 
        // index 0 (the beginning of the string):
        prefix = originalText.substr(0, prefixLength);
        // if settings.maxLength is less than 2 then the
        // suffix is an empty string (''), otherwise it's
        // a substring of the originalText, using a negative
        // index which takes the last 'suffixLength'
        // characters from the string:
        suffix = settings.maxLength < 2 ? '' : originalText.substr(-suffixLength);
        // here we set the innerHTML (so that we can use HTML
        // character-entities, such as '&hellip;') to the
        // prefix + the settings.ellipsis character(s) + the suffix:
        _this.innerHTML = prefix + settings.ellipsis + suffix;
    }
}
// Using Function.prototype.call() to use Array.prototype.forEach()
// on the array-like NodeList returned by document.querySelectorAll():
Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function (el) {
// the first argument (here: 'el') supplied to the function
// is the array-element (here a DOM node from the NodeList)
// from the array (NodeList) over which we're iterating.
    // using Function.prototype.apply() in order to specify
    // that 'this' in the function (centralEllipsis) will be
    // the supplied DOM node ('el'); the array is used to 
    // pass the arguments to the function, the empty object
    // is what will be the 'opts' variable in the function
    // called. It doesn't have to be there, it's simply left
    // in place to show how to pass arguments to the function,
    // and how to supply user-defined options to override the
    // the defaults:
    centralEllipsis.apply(el, [{}]);
});

function centralEllipsis(opts) {
  var settings = {
      'maxLength': 7,
      'ellipsis': '…',
      'writeToAttribute': 'data-originaltext'
    },
    _this = this;
  for (var prop in opts) {
    if (opts.hasOwnProperty(prop)) {
      settings[prop] = 'undefined' !== typeof opts[prop] ? opts[prop] : settings[prop];
    }
  }
  var prefixLength = Math.ceil(settings.maxLength / 2),
    suffixLength = settings.maxLength - prefixLength,
    originalText = _this.title = _this.textContent,
    prefix, suffix;
  if (settings.maxLength < originalText.length) {
    _this.setAttribute(settings.writeToAttribute, originalText);
    prefix = originalText.substr(0, prefixLength);
    suffix = settings.maxLength < 2 ? '' : originalText.substr(-suffixLength);
    _this.innerHTML = prefix + settings.ellipsis + suffix;
  }
}
Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function(el) {
  centralEllipsis.apply(el, [{}]);
});

<ul>
  <li class="midEllipsis">abcdefghijklm</li>
</ul>

外部 JS 小提琴演示，用于实验。

要覆盖默认设置，例如将maxLength设置为 4 ：

Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function(el) {
  centralEllipsis.apply(el, [{
    'maxLength': 4
  }]);
});

function centralEllipsis(opts) {
  var settings = {
      'maxLength': 7,
      'ellipsis': '…',
      'writeToAttribute': 'data-originaltext'
    },
    _this = this;
  for (var prop in opts) {
    if (opts.hasOwnProperty(prop)) {
      settings[prop] = 'undefined' !== typeof opts[prop] ? opts[prop] : settings[prop];
    }
  }
  var prefixLength = Math.ceil(settings.maxLength / 2),
    suffixLength = settings.maxLength - prefixLength,
    originalText = _this.title = _this.textContent,
    prefix, suffix;
  if (settings.maxLength < originalText.length) {
    _this.setAttribute(settings.writeToAttribute, originalText);
    prefix = originalText.substr(0, prefixLength);
    suffix = settings.maxLength < 2 ? '' : originalText.substr(-suffixLength);
    _this.innerHTML = prefix + settings.ellipsis + suffix;
  }
}
Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function(el) {
  centralEllipsis.apply(el, [{
    'maxLength': 4
  }]);
});

<ul>
  <li class="midEllipsis">abcdefghijklm</li>
</ul>

外部 JS 小提琴演示，用于实验。

或者要将'ellipsis'字符设置为"»"字符（例如）：

Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function(el) {
  centralEllipsis.apply(el, [{
    'ellipsis': '»'
  }]);
});

function centralEllipsis(opts) {
  var settings = {
      'maxLength': 7,
      'ellipsis': '…',
      'writeToAttribute': 'data-originaltext'
    },
    _this = this;
  for (var prop in opts) {
    if (opts.hasOwnProperty(prop)) {
      settings[prop] = 'undefined' !== typeof opts[prop] ? opts[prop] : settings[prop];
    }
  }
  var prefixLength = Math.ceil(settings.maxLength / 2),
    suffixLength = settings.maxLength - prefixLength,
    originalText = _this.title = _this.textContent,
    prefix, suffix;
  if (settings.maxLength < originalText.length) {
    _this.setAttribute(settings.writeToAttribute, originalText);
    prefix = originalText.substr(0, prefixLength);
    suffix = settings.maxLength < 2 ? '' : originalText.substr(-suffixLength);
    _this.innerHTML = prefix + settings.ellipsis + suffix;
  }
}
Array.prototype.forEach.call(document.querySelectorAll('.midEllipsis'), function(el) {
  centralEllipsis.apply(el, [{
    'ellipsis': '&raquo;'
  }]);
});

<ul>
  <li class="midEllipsis">abcdefghijklm</li>
</ul>

外部 JS 小提琴演示，用于实验。

引用：

• Array.prototype.forEach() .
• 条件（三元）运算符。
• document.querySelectorAll() .
• Element.innerHTML .
• Element.setAttribute() .
• Function.prototype.apply() .
• Function.prototype.call() .
• Node.textContent .
• String.prototype.substr() .
• typeof运算符。

您添加了 css 和 javascript 标签，因此我想到了一种暗示两种语言的解决方法。

您可以尝试下一个解决方法：
1.减去除最后三个字符以外的所有字符variable_a。减去variable_b最后三个字符。
2. 将variable_a扔进一个应用省略号的跨度中。
3.在第一个跨度之后立即添加另一个不带省略号的跨度，并用最后三个字符填充它（variable_b）