Insert ellipsis (…) into HTML tag if content too w

2018-12-31 10:46发布

站内问答 / JavaScript
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I have a webpage with an elastic layout that changes its width if the browser window is resized.

In this layout there are headlines (h2) that will have a variable length (actually being headlines from blogposts that I don't have control over). Currently - if they are wider than the window - they are broken into two lines.

Is there an elegant, tested (cross-browser) solution - for example with jQuery - that shortens the innerHTML of that headline tag and adds "..." if the text would be too wide to fit into one line at the current screen/container width?

24条回答
人间绝色
2楼-- · 2018-12-31 10:48

trunk8 jQuery plugin supports multiple lines, and can use any html, not just ellipsis characters, for the truncation suffix: https://github.com/rviscomi/trunk8

Demo here: http://jrvis.com/trunk8/

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美炸的是我
3楼-- · 2018-12-31 10:50

Just in case y'all end up here in 2013 - here is a pure css approach I found here: http://css-tricks.com/snippets/css/truncate-string-with-ellipsis/

.truncate {
  width: 250px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

It works well.

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零度萤火
4楼-- · 2018-12-31 10:50

I'd done something similar for a client recently. Here's a version of what I did for them (example tested in all latest browser versions on Win Vista). Not perfect all around the board, but could be tweaked pretty easily.

Demo: http://enobrev.info/ellipsis/

Code:

<html>
    <head>
        <script src="http://www.google.com/jsapi"></script>
        <script>            
            google.load("jquery", "1.2.6");
            google.setOnLoadCallback(function() {
                $('.longtext').each(function() {
                    if ($(this).attr('scrollWidth') > $(this).width()) {
                        $more = $('<b class="more">&hellip;</b>');

                        // add it to the dom first, so it will have dimensions
                        $(this).append($more);

                        // now set the position
                        $more.css({
                            top: '-' + $(this).height() + 'px',
                            left: ($(this).attr('offsetWidth') - $more.attr('offsetWidth')) + 'px'
                        });
                    }
                });
            });
        </script>

        <style>
            .longtext {
                height: 20px;
                width: 300px;
                overflow: hidden;
                white-space: nowrap;
                border: 1px solid #f00;
            }

            .more {
                z-index: 10;
                position: relative;
                display: block;
                background-color: #fff;
                width: 18px;
                padding: 0 2px;
            }
        </style>
    </head>
    <body>
        <p class="longtext">This is some really long text.  This is some really long text.  This is some really long text.  This is some really long text.</p>
    </body>
</html>
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长期被迫恋爱
5楼-- · 2018-12-31 10:50

I was a bit surprised by the behavior of the css though. 

var cssEllipsis = 
{   "width": "100%","display": "inline-block", 
"vertical-align": "middle", "white-space": "nowrap", 
"overflow": "hidden", "text-overflow": "ellipsis" 
};

Unless I provided the width to the control to which i needed to bind the ellipsis didn't suppost my cause. Is width a must property to be added ??? Please put your thoughts.

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荒废的爱情
6楼-- · 2018-12-31 10:50 
<html>
<head>
    <!-- By Warren E. Downs, copyright 2016.  Based loosely on a single/multiline JQuery using example by Alex,
    but optimized to avoid JQuery, to use binary search, to use CSS text-overflow: ellipsis for end,
    and adding marquee option as well.
    Credit: Marquee: http://jsfiddle.net/jonathansampson/xxuxd/
            JQuery version: http://stackoverflow.com/questions/536814/insert-ellipsis-into-html-tag-if-content-too-wide
            (by Alex, http://stackoverflow.com/users/71953/alex)
            (Improved with Binary Search as suggested by StanleyH, http://stackoverflow.com/users/475848/stanleyh)
    -->
    <meta content="text/html;charset=utf-8" http-equiv="Content-Type">
    <meta content="utf-8" http-equiv="encoding">
    <style>

        .single {
            overflow:hidden;
            white-space: nowrap;
            width: 10em;
            padding: 10px;
            margin: 0 auto;
            border: solid 1px blue;
        }

        .multiline {
            overflow: hidden;
            white-space: wrap;
            width: 10em;
            height: 4.5em;
            padding: 10px;
            margin: 0 auto;
            border: solid 1px blue;
        }

        .marquee {
            overflow: hidden;
            width: 40em;
            padding: 10px;
            margin: 0 auto;
            border: solid 1px blue;
        }

</style>
    <script>
        var _marqueeNumber=0;
        // mode=start,end,middle
        function clipText(text, len, mode) {
            if(!mode) { mode="end"; }
            else { mode=mode.toLowerCase(); }
            if(mode == "start") { return "&hellip;"+clipText(text,len,"_start"); }
            if(mode == "_start") { return text.substr(text.length - len); }
            if(mode == "middle") { 
                return clipText(text, len/2, "end") + clipText(text, len/2, "_start");
            }
            return text.substr(0, len) + "&hellip;";
        }

        function generateKeyframes(clsName, start, end) {
            var sec=5;
            var totalLen=parseFloat(start)-parseFloat(end);
            if(start.indexOf('em') > -1)      { sec=Math.round(totalLen/3); }
            else if(start.indexOf('px') > -1) { sec=Math.round(totalLen/42); }

            var style = document.createElement('style');
            style.type = 'text/css';
            style.innerHTML = 'body {}';
            document.getElementsByTagName('head')[0].appendChild(style);
            this.stylesheet = document.styleSheets[document.styleSheets.length-1];
            try {
                this.stylesheet.insertRule('.'+clsName+' {\n'+
                    '    animation: '+clsName+' '+sec+'s linear infinite;\n'+
                    '}\n', this.stylesheet.rules.length);
                this.stylesheet.insertRule('.'+clsName+':hover {\n'+
                    '    animation-play-state: paused\n'+
                    '}\n', this.stylesheet.rules.length);
                this.stylesheet.insertRule('@keyframes '+clsName+' {\n'+
                    '    0%   { text-indent: '+start+' }\n'+
                    '    100% { text-indent: '+end+' }\n'+
                    '}', this.stylesheet.rules.length);
            } catch (e) {
                console.log(e.message);
            }
        }

        function addClone(el, multiline, estyle) {
            if(!estyle) { 
                try { estyle=window.getComputedStyle(el); }
                catch(e) { return null; }
            }
            var t = el.cloneNode(true);
            var s=t.style;
            //s.display='none';
            s.visibility='hidden'; // WARNING: Infinite loop if this is not hidden (e.g. while testing)
            s.display='inline-block';
            s.background='black';
            s.color='white';
            s.position='absolute';
            s.left=0;
            s.top=0;
            s.overflow='visible';
            s.width=(multiline ? parseFloat(estyle.width) : 'auto');
            s.height=(multiline ? 'auto' : parseFloat(estyle.height));

            el.parentNode.insertBefore(t, el.nextSibling);

            return t;
        }
        function getTextWidth(el, multiline) {
            var t=addClone(el, multiline);
            if(!t) { return null; }
            var ts=window.getComputedStyle(t);
            var w=ts.width;
            if(multiline) {
                var es=window.getComputedStyle(el);
                var lines=Math.round(parseInt(ts.height)/parseInt(es.height))*2+0.5;
                w=w+'';
                var unit=''; // Extract unit
                for(var xa=0; xa<w.length; xa++) {
                    var c=w[xa];
                    if(c <= '0' || c >= '9') { unit=w.substr(xa-1); }
                }
                w=parseFloat(w);
                w*=lines; // Multiply by lines
                w+=unit; // Append unit again
            }
            t.parentNode.removeChild(t);
            return w;
        }

        // cls=class of element to ellipsize
        // mode=start,end,middle,marq (scrolling marquee instead of clip)
        function ellipsis(cls, mode) {
            mode=mode.toLowerCase();
            var elems=document.getElementsByClassName(cls);
            for(xa in elems) {
                var el=elems[xa];
                var multiline = el.className ? el.className.indexOf('multiline') > -1 : true;
                if(mode == "marq") {       
                    var w=getTextWidth(el, multiline);
                    if(!w) { continue; }
                    var mCls="dsmarquee"+(_marqueeNumber++);
                    var es=window.getComputedStyle(el);
                    generateKeyframes(mCls,es.width, '-'+w);
                    el.className+=" "+mCls; 
                    continue; 
                }
                if(mode == "end" && !multiline) { el.style.textOverflow="ellipsis"; continue; }
                var estyle=null;
                try { estyle=window.getComputedStyle(el); }
                catch(e) { continue; }
                if(estyle.overflow == "hidden") {
                    var text = el.innerHTML;
                    var t=addClone(el, multiline, estyle);

                    function height() {
                        var ts=window.getComputedStyle(t);
                        var es=window.getComputedStyle(el);
                        return parseFloat(ts.height) - parseFloat(es.height); 
                    }
                    function width() { 
                        var ts=window.getComputedStyle(t);
                        var es=window.getComputedStyle(el);
                        return parseFloat(ts.width) - parseFloat(es.width); 
                    }

                    var tooLong = multiline ? height : width;

                    var len=text.length;
                    var diff=1;
                    var olen=0;
                    var jump=len/2;
                    while (len > 0) {
                        var diff=tooLong();
                        if(diff > 0) { len-=jump; jump/=2; }
                        else if(diff < 0) { len+=jump; }
                        len=Math.round(len);
                        //alert('len='+len+';olen='+olen+';diff='+diff+';jump='+jump+';t='+JSON.stringify(t.innerHTML));
                        t.innerHTML=clipText(text, len, mode);
                        if(olen == len) { break; }
                        olen=len;
                    }
                    el.innerHTML=t.innerHTML;
                    t.parentNode.removeChild(t);
                }           
                //break;
                t.style.visibility='hidden';
            }
        }

        function testHarness() {
            ellipsis('ellipsis1', 'start'); 
            ellipsis('ellipsis2', 'end'); 
            ellipsis('ellipsis3', 'middle'); 
            ellipsis('marquee', 'marq')
        }
    </script>
    </head>
    <body onload="testHarness()">
    <div class="single ellipsis1" style="float:left">some long text that should be clipped left</div>
    <div class="single ellipsis2" style="float:right">right clip long text that should be clipped</div>
    <div class="single ellipsis3" style="float:center">some long text that should be clipped in the middle</div>

    <br />

    <p class="single marquee">Windows 8 and Windows RT are focused on your life—your friends and family, your apps, and your stuff. With new things like the <a href="http://windows.microsoft.com/en-US/windows-8/start-screen">Start screen</a>, <a href="http://windows.microsoft.com/en-US/windows-8/charms">charms</a>, and a <a href="http://windows.microsoft.com/en-US/windows-8/microsoft-account">Microsoft account</a>, you can spend less time searching and more time doing.</p>
    &nbsp;

    <br />

    <div class="multiline ellipsis1" style="float:left">Test test test test test test, some more long text, such as asdasdasdasdasd, that should be multiline clipped left(*)</div>

    <div class="multiline ellipsis2" style="float:right">right clip multiline long text, such as Test test test test test test, and some more long text that should be multiline clipped right.</div>

    <div class="multiline ellipsis3" style="float:center">Test test test test test test, some more long text, such as asdasdasdasdasd, that should be multiline clipped in the middle(*)</div>

    <br />

    <p class="multiline marquee">Multiline Marquee: Windows 8 and Windows RT are focused on your life—your friends and family, your apps, and your stuff. With new things like the <a href="http://windows.microsoft.com/en-US/windows-8/start-screen">Start screen</a>, <a href="http://windows.microsoft.com/en-US/windows-8/charms">charms</a>, and a <a href="http://windows.microsoft.com/en-US/windows-8/microsoft-account">Microsoft account</a>, you can spend less time searching and more time doing.</p>
    &nbsp;

    </body>
</html>
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忆尘夕之涩
7楼-- · 2018-12-31 10:51

My answer only supports single line text. Check out gfullam's comment below for the multi-line fork, it looks pretty promising.

I rewrote the code from the first answer a few times, and I think this should be the fastest.

It first finds an "Estimated" text length, and then adds or removes a character until the width is correct.

The logic it uses is shown below:

enter image description here

After an "estimated" text length is found, characters are added or removed until the desired width is reached.

I'm sure it needs some tweaking, but here's the code:

(function ($) {
    $.fn.ellipsis = function () {
        return this.each(function () {
            var el = $(this);

            if (el.css("overflow") == "hidden") {
                var text = el.html().trim();
                var t = $(this.cloneNode(true))
                                        .hide()
                                        .css('position', 'absolute')
                                        .css('overflow', 'visible')
                                        .width('auto')
                                        .height(el.height())
                                        ;
                el.after(t);

                function width() { return t.width() > el.width(); };

                if (width()) {

                    var myElipse = "....";

                    t.html(text);

                    var suggestedCharLength = (text.length * el.width() / t.width()) - myElipse.length;

                    t.html(text.substr(0, suggestedCharLength) + myElipse);

                    var x = 1;
                    if (width()) {
                        while (width()) {
                            t.html(text.substr(0, suggestedCharLength - x) + myElipse);
                            x++;
                        }
                    }
                    else {
                        while (!width()) {
                            t.html(text.substr(0, suggestedCharLength + x) + myElipse);
                            x++;
                        }
                        x--;
                        t.html(text.substr(0, suggestedCharLength + x) + myElipse);
                    }

                    el.html(t.html());
                    t.remove();
                }
            }
        });
    };
})(jQuery);
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