How to select nth line of text (CSS/JS)

Question

How to select and apply style on a specific line of text? Like the CSS pseudo-element :first-line, but I want to select any line, not limited to the first.

It seems that it can't be done by using only CSS... Anyway I don't mind a JS solution.

---

Update:

Well, actually it's only for interest. I'm trying to achieve something like highlighting every even row of a paragraph (for readability, like what everyone does for table rows)...

Pre-formating the text like:

<p>
<span class='line1'>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do </span>
<span class='line2'>eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad </span>
<span class='line3'>minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip </span>
<span class='line4'>ex ea commodo consequat. Duis aute irure dolor in reprehenderit in </span>
<span class='line5'>voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur </span>
<span class='line6'>sint occaecat cupidatat non proident, sunt in culpa qui officia </span>
<span class='line7'>deserunt mollit anim id est laborum.</span>
</p>

...it is ok for me, but how to know where to split? Even if the width of paragraph is given, it is still hard to determine...

Answer 1

Interesting. You can do something like that with JavaScript:

$(function(){ 
  var p = $('p'); 
  var words = p.text().split(' '); 
  var text = ''; 
  $.each(words, function(i, w){
                   if($.trim(w)) text = text + '<span>' + w + '</span> ' }
        ); //each word 
  p.html(text); 
  $(window).resize(function(){ 

    var line = 0; 
    var prevTop = -15; 
    $('span', p).each(function(){ 
      var word = $(this); 
      var top = word.offset().top; 
      if(top!=prevTop){ 
        prevTop=top; 
        line++; 
      } 
      word.attr('class', 'line' + line); 
    });//each 

  });//resize 

  $(window).resize(); //first one
});

Basically, we wrap each word with a span, and add a class based on the position of the span, whenever the window resizes. I'm sure it can be done more efficiently, but it works as a proof of concept. Of course, for even/odd lines, you can simplify the code.

Edge cases: I didn't test it where the class changes the size or width of the words. It may end up very wrong.

Here it is in action: https://jsbin.com/piwizateni/1/edit?html,css,js,output

Answer 2

If each line is a separate <li> or <p> you can select that, using CSS.

:nth-child(N)

Taken from sitepoint.com, works in in Opera 9.5+, Safari 4+, FF3.5+

Description

This pseudo-class matches elements on the basis of their positions within a parent element’s list of child elements. The pseudo-class accepts an argument, N, which can be a keyword, a number, or a number expression of the form an+b. For more information, see Understanding :nth-child Pseudo-class Expressions.

If N is a number or a number expression, :nth-child(N) matches elements that are preceded by N-1 siblings in the document tree.

The following example selectors are equivalent, and will match odd-numbered table rows:

tr:nth-child(2n+1) {
  ⋮ declarations
}
tr:nth-child(odd) {
  ⋮ declarations
}

This example selector will match the first three rows of any table:

tr:nth-child(-n+3) {
  ⋮ declarations
}

This example selector will match any paragraph that’s the first child element of its parent element:

p:nth-child(1) {
  ⋮ declarations
}

This is, of course, equivalent to the selector p:first-child.

Example

This example selector will match odd-numbered table rows:

tr:nth-child(odd) {
  ⋮ declarations
}

You can also use jQuery.