gistfile1.js

function getSelectionString(el, win) {
    win = win || window;
    var doc = win.document, sel, range, prevRange, selString;
    if (win.getSelection && doc.createRange) {
        sel = win.getSelection();
        if (sel.rangeCount) {
          prevRange = sel.getRangeAt(0);
        }
        range = doc.createRange();
        range.selectNodeContents(el);
        sel.removeAllRanges();
        sel.addRange(range);
        selString = sel.toString();
        sel.removeAllRanges();
        prevRange && sel.addRange(prevRange);
    } 
    else if (doc.body.createTextRange) {
        range = doc.body.createTextRange();
        range.moveToElementText(el);
        range.select();
    }
    return selString;
}