Summaries by using my fork of textteaser!

Console based injection.js

// Open the debug tools
// load the function using
// This requires the target site to have jquery loaded as $
$('<script src="https://rawgithub.com/skmp/textteaser/master/tease.js"></script>').appendTo('body');

//Use directly from console
//(replace with proper selectors for your page)
tease($('.title-selector').text(), $('.content-selector').text())

yoursite.html

<!-- Load after jquery  -->

<script src="https://rawgithub.com/skmp/textteaser/master/tease.js"></script>

<!-- .... -->
<script>
    tease($('.title-selector').text(), $('.content-selector').text())
</script>