gistfile1.js

var rect = { 
	leftTop: {x: $this.offset().left + 2, y: $this.offset().top + lineHeight / 2}, 
	bottomRight: {x: $this.offset().left + $this.width() - 2, y: $this.offset().top + limitHeight - lineHeight / 2}
};
var rangeStart = doc.caretRangeFromPoint(rect.leftTop.x, rect.leftTop.y);
var rangeEnd = doc.caretRangeFromPoint(rect.bottomRight.x, rect.bottomRight.y);

var range = doc.createRange();
range.setStart(rangeStart.startContainer, rangeStart.startOffset);
range.setEnd(rangeEnd.startContainer, rangeEnd.startOffset);

var html = $('<div>').append($(range.cloneContents())).html();