Jquery - Truncate Text by Line (not by chart-count)

Question

Dear All,

I need a Jquery script to truncate a text paragraph by line (not by chart count).

I would like to achieve an evenly truncated text-block. It should have a "more" and "less" link to expand and shorten the text paragraph. My text paragraph is wrapped in a div with a class, like this:

<div class="content">
<h2>Headline</h2>
<p>The paragraph Text here</p>
</div>

The closest solution i could find on SOF is the one below (but it`s for textarea element and does not work for me): http://stackoverflow.com/questions/556767/limiting-number-of-lines-in-textarea

Many thanks for any tips. Ben

Answer 1

If you used a monospaced font, you'd have a shot at this working, as you'd have a good idea how many letters fit onto each line, for an element of a defined width. However, if a word breaks across lines, then this might get tricky..

e: found another question which is basically what you're after - they didn't really have a resolution either, but to my mind, the line-height and element height seems closest.

"How can I count text lines inside a dom element"

Answer 2

why not make the p element with overflow: hidden; give fixed line height, caluclate the height of the div so id contains exactly the number of lines you require and the only change the height of the p from javascript.

p{
    overflow:hidden;
    line-height:13px;
    height:26px; /* show only 2 rows */
}
<script type="text/javascript">
    function seeMoreRows(){
        $(p).height("52px");
    }
</script>

Answer 3

For a basic approach, you could take a look at the line-height CSS property and use that in your calculations. Bear in mind that this approach will not account for other inline elements that are larger than that height (e.g. images).

If you want something a bit more advanced, you can get the information about each line using getClientRects() function. This function returns a collection of TextRectangle objects with width, height and offset for each one.

See this answer here for an example (albeit an unrelated goal) of how getClientRects() works.

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Update, had a bit of time to come back and update this answer with an actual example. It's basic, but you get the idea:

http://jsbin.com/ukaqu3/2

A couple of pointers:

• The collection returned by getClientRects is static, it won't update automatically if the containing element's dimensions change. My example works around this by capturing the window's resize event.

• For some strange standards-compliance reason that I'm not understanding, the element you call getClientRects on must be an inline element. In the example I have, I use a container div with the text in another div inside with display: inline.