This is one your are looking for i believe:
text = window.getSelection().toString();
Hide selected/highlighted text javascript
You have to get parent of Element from DOM:
function getSelectionParentElement() {
var parentEl = null, sel;
if (window.getSelection) {
sel = window.getSelection();
if (sel.rangeCount) {
parentEl = sel.getRangeAt(0).commonAncestorContainer;
if (parentEl.nodeType != 1) {
parentEl = parentEl.parentNode;
}
}
} else if ( (sel = document.selection) && sel.type != "Control") {
parentEl = sel.createRange().parentElement();
}
return parentEl;
}
Update
Fixed demo to hide text we have to find startOffset
function getStartOffset() {
var sel = document.selection, range, rect;
var x = 0, y = 0;
if (sel) {
if (sel.type != "Control") {
range = sel.createRange();
range.collapse(true);
}
} else if (window.getSelection) {
sel = window.getSelection();
if (sel.rangeCount) {
range = sel.getRangeAt(0).cloneRange();
if (range.getClientRects) {
range.collapse(true);
}
}
}
return range.startOffset;
}