[thelist] counting rendered lines of text

Jonathan Snook jonathan.snook at gmail.com
Thu Jun 14 12:36:48 CDT 2007

On 6/14/07, sbeam <sbeam at syxyz.net> wrote:
> Say you have a container of a fixed width with some text in it. Is there
> any way to count the number of lines in the text, as rendered?

Here's a quick script I threw together. Keep in mind, it doesn't
account for padding, margins, borders or inline elements that exceed
the line height and I haven't tested it in anything but Firefox. I did
a variation that simply truncated it word by word until it fell under
the appropriate line height.

Hopefully this gets you going in the right direction.

 el = the element I want to shorten
 lines = the # of lines to shorten to
function shorten(el, lines)
  var height, tmp;

  // determine line height by putting a space into the
  // container and grabbing the height of the container
  tmp = el.innerHTML;
  el.innerHTML = '&nbsp;';
  height = el.offsetHeight;
  el.innerHTML = tmp;

  var fullheight = el.offsetHeight;
  // find out how many lines of text I have
  var divisor = fullheight / height;
  tmp = el.innerHTML.substr(0, el.innerHTML.length / divisor * lines);
  el.innerHTML = tmp.substr(0, tmp.lastIndexOf(' ')) + '&hellip;';

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