How to get the position of text within an element?

Question

If I have an element, for instance:

<p>Lorem ipsum dolor sit amet, ante risus massa adipiscing quisque quis. At mauris tellus in, sed vehicula integer fermentum rhoncus at faucibus, in vitae purus. Maecenas in vel ligula orci tellus ac, fringilla conubia lorem elit. Dui nulla sodales morbi vel. Massa sed viverra. Maecenas imperdiet donec urna a, ligula sed</p>

And this is flowed across multiple lines:

Lorem ipsum dolor sit amet, ante risus massa adipiscing
quisque quis. At mauris tellus in, sed vehicula integer
fermentum rhoncus at faucibus, in vitae purus. Maecenas
in vel ligula orci tellus ac, fringilla conubia lorem
elit. Dui nulla sodales morbi vel. Massa sed viverra.
Maecenas imperdiet donec urna a, ligula sed

Is it possible to find out the position (in x,y-coordinates) of a particular character in the text using Javascript? If not, could I get the y-position of each line in the text?

Please note : There is a lot of text in the <p> tag in my application, so adding <span> around each character/word would be too much processing.

Answer 1

You can use ranges to find the position of elements. Quick jsfiddle here: https://jsfiddle.net/abrady0/ggr5mu7o/

var range = document.createRange();
range.setStart(parentElt, start);
range.setEnd(parentElt, end);
// These rects contain the client coordinates in top, left
var rects = range.getClientRects();

Edit: modified to print out the coordinates of the matched rect

Answer 2

If you know the string position of the character in the text, you can wrap the character in a <span> or similar element with an ID and find the x,y coords of that element. Easiest way to do this is with jQuery or another library, see this answer for a cross-browser, no-library method.

Answer 3

我得到的想法是 - 获取所有文本，将所需的子字符串打包到span-s中，替换element的innerHTML，并获取span-s的位置