Select First 300 Characters In A Div?

I have got a code which selects the whole text inside a div element on base of its id. But I need to modify it to select the lets say first 300 characters. Can someone suggest something. It is related to moving end of range. I will also keep trying... Here comes the code

Code:

var textC=document.getElementById(divID);
if (document.selection)
{
var div = document.body.createTextRange();

[Code].....

Only tested with FF3 , else part works fine for FF3 but need to move end point of range ... and stuck here