How to Get the Dom Element Which Contains the Current Selection

How can I get the DOM element which contains the current selection?

In IE, use document.selection.createRange().parentElement() and in real browsers use window.getSelection().getRangeAt(0).startContainer.parentNode. Something like this:

function getSelectedNode()
{
    if (document.selection)
        return document.selection.createRange().parentElement();
    else
    {
        var selection = window.getSelection();
        if (selection.rangeCount > 0)
            return selection.getRangeAt(0).startContainer.parentNode;
    }
}

Determine which DOM elements the current text selection contains

window.getSelection() gives you a Selection object. Use selection.rangeCount and selection.getRangeAt() to get a Range object representing which selection you want.

Now you can get the first and last nodes in the selection from range.startContainer/startOffset and range.endContainer/endOffset. You could then walk up and down the tree to pick up all the elements in between those two positions, eg. using the getElementsBetweenTree() function from this answer.

Unfortunately, IE's TextRange model is totally different to the W3 and HTML5 standard, and in general much worse. It does't give up the start and end positions nearly as easily, and not in any reliable way. All you get is parentElement to tell you the common ancestor, and from there you're limited to guessing where the range is based on creating a new Range and calling moveToElementText on it then compareEndPoints with the selection range. And if you need to know the exact text selection you're then guessing based on moveStart/moveEnding the range and comparing, which isn't fun at all.

how to get selected DOM using javascript if selected text is HTML?

You can try this approach.. (if only you've direct text node in your div)

window.getSelection().focusNode.parentElement     //returns the selected element

so you can set attr like

window.getSelection().focusNode.parentElement.setAttribute('data-id', 'id-1');

You can wrap it in a 'mouseup' event with your current div

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <div id="myDiv">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Id natus voluptatibus eum explicabo soluta excepturi?
    </div>
    <div id="myDiv2">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Id natus voluptatibus eum explicabo soluta excepturi?
    </div>

    <script>
        var myDiv = document.getElementById('myDiv')
        myDiv.addEventListener('mouseup', function(){
            window.getSelection().focusNode.parentElement.setAttribute('data-id', 'id-1');
        })
    </script>
</body>
</html>

Or it is best approach to add attr to selected 'div' only, if there is many divs

var div = document.querySelectorAll('div')
for(var i = 0; i < div.length; i++){
    div[i].addEventListener('mouseup', function(){
     window.getSelection().focusNode.parentElement.setAttribute('data-id', 'id-1');
    }, false)
}

DOM find current selected drop down element

Option 1

HTML

<select id="Quantity" name="Quantity" 
        class="quantity_select" onchange="SetValue(this.value)>
    <option id="1" selected="selected" value="1">1</option>
    <option id="2" value="2">2</option>
    <option id="3" value="3">3</option>
</select>

JavaScript

function SetValue(val) {
    alert(val); // This will be the selected value in the drop down
}

Option 2

If you already have JS in place, and don't want to use option 1, you can simply get the value with getElementById():

var ddl = document.getElementById('Quantity');
var val = ddl.options[ddl.selectedIndex].value;

How can I get the element in which highlighted text is in?

Try something similar to this to get the dom element that contains the selected text.

window.getSelection().anchorNode.parentNode

It works on firefox and Chrome, you should test it into the remaining browsers.

It have a quirk, if you select text that beholds to more than an element, only the first one is returned. But maybe you can live with this.

Just for reference on what is the anchorNode property:
http://help.dottoro.com/ljkstboe.php

On internet explorer this snippet should do the trick (I can't test it)

document.selection.createRange().parentElement();

as stated into
http://msdn.microsoft.com/en-us/library/ms535872.aspx and
http://msdn.microsoft.com/en-us/library/ms536654.aspx

A range explanation on quirksmode: http://www.quirksmode.org/dom/range_intro.html

How to know if there is a link element within the selection

I ended up going with a solution like this:

        var findinselection = function(tagname, container) {
            var
                i, len, el,
                rng = getrange(),
                comprng,
                selparent;
            if (rng) {
                selparent = rng.commonAncestorContainer || rng.parentElement();
                // Look for an element *around* the selected range
                for (el = selparent; el !== container; el = el.parentNode) {
                    if (el.tagName && el.tagName.toLowerCase() === tagname) {
                        return el;
                    }
                }
                // Look for an element *within* the selected range
                if (!rng.collapsed && (rng.text === undefined || rng.text) &&
                    selparent.getElementsByTagName) {
                    el = selparent.getElementsByTagName(tagname);
                    comprng = document.createRange ?
                        document.createRange() : document.body.createTextRange();
                    for (i = 0, len = el.length; i < len; i++) {

                        // determine if element el[i] is within the range
                        if (document.createRange) { // w3c
                            comprng.selectNodeContents(el[i]);
                            if (rng.compareBoundaryPoints(Range.END_TO_START, comprng) < 0 &&
                                rng.compareBoundaryPoints(Range.START_TO_END, comprng) > 0) {
                                return el[i];
                            }
                        }
                        else { // microsoft
                            comprng.moveToElementText(el[i]);
                            if (rng.compareEndPoints("StartToEnd", comprng) < 0 &&
                                rng.compareEndPoints("EndToStart", comprng) > 0) {
                                return el[i];
                            }
                        }
                    }
                }
            }
        };

Where getrange() is another function of mine to get the current selection as a range object.

To use, call it like

var link = findselection('a', editor);

Where editor is the contenteditable element, or body in a designmode iframe.

Replicate HTML source of a DOM element in current state

You could just wrap your select in another element. Then you'd be able to select it by id, get the parent node, then the parent node's innerHTML. If you want to show which option is currently selected, you can place the selected attribute on it.

document.getElementById('selectId').addEventListener('change', function() {    var opts = this.getElementsByTagName('option');    for (var i = 0; i < opts.length; i++)        opts[i].removeAttribute('selected');    this.querySelector('option:checked').setAttribute('selected', 'selected');    console.log(this.parentNode.innerHTML);});

<div class="select-wrapper">  <select id="selectId">    <option>Yes</option>    <option>No</option>  </select></div>