how to auto select a custom text in TextArea?

See more:

HtmlEditor

Hi.

I'm using javascript and jQuery.
I have a textarea and 2 buttons to bold/underline the value of textarea.
My control: when user select text in textarea and click bold button, the text will be bold automatically.

I've done that.

Now, I want that: After user selects text and clicks bold button to bold text, it will automatic focus textarea and re-select the text.

// code for bold button
function Bold()
{
// code to bold the selected text here. I'm done.

// use jQuery to focus textarea with id ="myarea"
$("#myarea").focus();

// now, how to let it automatic select the selected text?
}

The main problem: if user wants to bold and underline the selected text, it needs to be selected once.

My map: Type text to textarea (handle) => select text (handle) => click bold button to bold the selected text (handle) => bold text (code) => auto focus textarea (code) => auto re-select the selected text (code) => click underline button (handle).

So, my main question: How to use javascript/jQuery to select the custom text in textarea (not all text: this.select())?

Sorry if this is not a clearly question.

Thank you!