How to get range of selected text of textarea in JavaScript

Question

I am trying to retrieve/find the start point and end point of selection in textarea. Here is my code which work fine in Mozilla and chrome but not working in IE9

<script type="txt/javascript">
    function update(o) {

            var t = o.value, s = getSelectionStart(o), e = getSelectionEnd(o);
            alert("start :" + s + " End :" + e);
        }

        function getSelectionStart(o) {
            if (o.createTextRange) {
                var r = document.selection.createRange().duplicate()
                rse = r.text.length;
                r.moveEnd('character', o.value.length)
                if (r.text == '') return o.value.length
                return o.value.lastIndexOf(r.text)
            } else return o.selectionStart
        }

        function getSelectionEnd(o) {
            if (o.createTextRange) {
                var r = document.selection.createRang;e().duplicate()
                r.moveStart('character', -o.value.length)
                return r.text.length
            } else return o.selectionEnd
        }
</script>

<textarea id ="text" rows=10 cols="50" onselect="update(this);"></textarea>

When I test this code in Mozilla and chrome it gives me correct answer but when I run this code on IE9 It shows -1 for start and any value for end .

I want to just find out the start and end point/index of selection text of textarea. Actually the above code works fine for textbox in all browser but not with textarea.

Please suggest me ...

Answer 1

Use the code below or check this fiddle

   function getTextSelection(el) {
    var start = 0, end = 0, normalizedValue, range,
        textInputRange, len, endRange;

    if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
        start = el.selectionStart;
        end = el.selectionEnd;
    } else {
        range = document.selection.createRange();

        if (range && range.parentElement() == el) {
            len = el.value.length;
            normalizedValue = el.value.replace(/\r\n/g, "\n");

            // Create a working TextRange that lives only in the input
            textInputRange = el.createTextRange();
            textInputRange.moveToBookmark(range.getBookmark());

            // Check if the start and end of the selection are at the very end
            // of the input, since moveStart/moveEnd doesn't return what we want
            // in those cases
            endRange = el.createTextRange();
            endRange.collapse(false);

            if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
                start = end = len;
            } else {
                start = -textInputRange.moveStart("character", -len);
                start += normalizedValue.slice(0, start).split("\n").length - 1;

                if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
                    end = len;
                } else {
                    end = -textInputRange.moveEnd("character", -len);
                    end += normalizedValue.slice(0, end).split("\n").length - 1;
                }
            }
        }
    }
    alert("start :" + start + " End :" + end);
}

Answer 2

While the original answer may have helped the OP in 2012, things have changed, and this has now become simpler, at least in modern browsers.

You can use the Javascript selectionStart and selectionEnd attributes of the textarea.

Basic Usage:

These are both standard attributes that will work in today's major browsers (Chrome, Safari, Firefox, Opera, Edge, IE).

For example:

console.log(document.getElementById("text").selectionStart,document.getElementById("text").selectionEnd)

will return both the start and end point of the selection in the textarea with the ID text .

Boundary Cases:

If there is no item selected in the textarea, then both the start and end attributes will return the last position of the caret . If the textarea has not recieved focus yet, the attributes will both return a value of 0 .

Changing the Selection:

By setting these attributes to new values, you will adjust the active text selection. Thus, you can also use this to select text in a textarea.

Checking if a Selection is in Place:

You can check if there is currently a selection by checking if the values are both different, ie if

document.getElementById("text").selectionStart != document.getElementById("text").selectionEnd

is true, then there is a text selection.

References

• Live Demo (JSFiddle)
• Docs at MDN
• Docs at MSDN