dom range.setStart / setEnd

Question

I am trying to bold only the text hel in this fiddle http://jsfiddle.net/yarkpakv/ but it does not seem to be working, what am I doing wrong???

var range = document.createRange();
var root_node = document.getElementById("test");

range.setStart(root_node,0);
range.setEnd(root_node,3);

var newNode = document.createElement("b");

range.surroundContents(newNode);

<div id="test">
    <p>h</p>ello    
</div>

Answer 1

You need to visualize the DOM structure of your <div id="test"> element. It contains three children:

1. A text node that contains only white space.

2. The <p> element which contains a text node that has the value h.

3. A text node that has the value ello.

So your range must start with the <p> element and ends in the ello text node, between the two l characters. Therefore:

var range = document.createRange();
var root_node = document.getElementById("test");

// Start at the `<p>` element.
range.setStart(root_node, 1); 

// End in the `ello` text node, between the two `l`s.
range.setEnd(root_node.childNodes[2], 2); 

var newNode = document.createElement("b");

range.surroundContents(newNode);

Here's a fiddle.