Get character position and select in Web browser control on mouse hover event

Question

In WebBrowser control I have the text like:
webbrowser.DocumentText = "Fifth You can also format text directly by using the other controls on the Home tab. Most controls offer a choice of using the look from the current theme or using a format that you specify directly."; 

When Mouse Hover event I want to get the specific word where the mouse position and the character position of that word.