Caret positition / Selection inside DIV, Textbox, Textarea, etc

Question

Is there a total solution for getting a caret position and/or selection inside every browser from different elements. I'm looking for a solution witch I can execute like mGetCaretPosition(iControl) witch will return the caret position inside it`s element.

I have tried a lot of functions:

• selection (window/document) [document=IE, window=Opera]
• getSelection (window/document) [document=Firefox, document=Chrome, document=Safari]
• selectionStart (input/textarea) [All]
• craeteRange (selection)
• createTextRange (selection)

Calling a method like document.selection.createRange().text doesn't return a caret position because it doesn't have a selection. When setting tRange.moveStart('character', -X) the X isn't a known value. When you use this inside a div and the caret is in the middle it takes the code before the div.

Answer 1

I have build this today. It`s a combination of youre response alex and al the other results inside google. I have tested it inside the browsers IE9, Chrome, Opera, Safari and Firefox on the PC and also on a HTC Sensation with Android with the default browser, Firefox, Chrome and Opera.

Only the Opera on the mobile device did have some troubles.

My solution:

// Control
var BSControl = function(iControl)
{
    // Variable
    var tControl = (typeof iControl == 'string' ? document.getElementById(iControl) : iControl);

    // Get Caret
    this.mGetCaret = function()
    {
        // Resultaat aanmaken
        var tResult = -1;

        // SelectionStart
        // *) Input & Textarea
        if(tResult == -1 && (tControl.selectionStart || tControl.selectionStart == '0'))
        {
            tResult = tControl.selectionStart;
        }

        // ContentWindow.GetSelection
        // *) IFrame
        if(tResult == -1 && (tControl.contentWindow && tControl.contentWindow.getSelection))
        {
            var tRange= tControl.contentWindow.getSelection().getRangeAt(0); 
            tResult = tRange.startOffset;
        }

        // GetSelection
        // *) Div
        if(tResult == -1 && (window.getSelection))
        {
            var tRange= window.getSelection().getRangeAt(0); 
            tResult = tRange.startOffset;
        }

        // Resultaat teruggeven
        return tResult;
    }

    // Set Caret
    this.mSetCaret = function(iPosition)
    {
        // SelectionStart
        // *) Input & Textarea
        if(tControl.selectionStart || tControl.selectionStart == '0')
        {
            tControl.selectionStart = iPosition;
            tControl.selectionEnd = iPosition;
            return;
        }

        // ContentWindow.GetSelection
        // *) IFrame
        if(tControl.contentWindow && tControl.contentWindow.getSelection)
        {
            var tRange = tControl.contentDocument.createRange();
            tRange.setStart(tControl.contentDocument.body.firstChild, iPosition);
            tRange.setEnd(tControl.contentDocument.body.firstChild, iPosition);

            var tSelection = tControl.contentWindow.getSelection();
            tSelection.removeAllRanges();
            tSelection.addRange(tRange);

            return;
        }

        // GetSelection
        // *) Div
        if(window.getSelection)
        {
            var tSelection = window.getSelection();
            var tRange= tSelection.getRangeAt(0); 

            tRange.setStart(tControl.firstChild, iPosition);
            tRange.setEnd(tControl.firstChild, iPosition);

            tSelection.removeAllRanges();
            tSelection.addRange(tRange);

            return;
        }
    }

    // Get Selection
    this.mGetSelection = function()
    {
        // Resultaat aanmaken
        var tResult = null;

        // SelectionStart
        // *) Input & Textarea
        if(tResult == null && (tControl.selectionStart || tControl.selectionStart == '0'))
        {
            tResult = this.mGet().substring(tControl.selectionStart, tControl.selectionEnd);
        }

        // ContentWindow.GetSelection
        // *) IFrame
        if(tResult == null && (tControl.contentWindow && tControl.contentWindow.getSelection))
        {
            var tSelection = tControl.contentWindow.getSelection() 
            tResult = tSelection.toString();
        }

        // GetSelection
        // *) Div
        if(tResult == null && (window.getSelection))
        {
            var tSelection = window.getSelection() 
            tResult = tSelection.toString();
        }

        // Resultaat teruggeven
        return tResult;
    }

    // Set Selection
    this.mSetSelection = function(iFrom, iUntil)
    {
        // SelectionStart
        // *) Input & Textarea
        if(tControl.selectionStart || tControl.selectionStart == '0')
        {
            tControl.selectionStart = iFrom;
            tControl.selectionEnd = iUntil;
            return;
        }

        // ContentWindow.GetSelection
        // *) IFrame
        if(tControl.contentWindow && tControl.contentWindow.getSelection)
        {
            var tRange = tControl.contentDocument.createRange();
            tRange.setStart(tControl.contentDocument.body.firstChild, iFrom);
            tRange.setEnd(tControl.contentDocument.body.firstChild, iUntil);

            var tSelection = tControl.contentWindow.getSelection();
            tSelection.removeAllRanges();
            tSelection.addRange(tRange);

            return;
        }

        // GetSelection
        // *) Div
        if(window.getSelection)
        {
            var tSelection = window.getSelection();
            var tRange= tSelection.getRangeAt(0); 

            tRange.setStart(tControl.firstChild, iFrom);
            tRange.setEnd(tControl.firstChild, iUntil);

            tSelection.removeAllRanges();
            tSelection.addRange(tRange);

            return;
        }
    }

    // Set
    this.mSet = function(iValue)
    {
        // Afhankelijk van aanwezige property waarde instellen
        if('value' in tControl)
        {
            tControl.value = iValue;
        }else if('innerText' in tControl)
        {
            tControl.innerText = iValue;
        }else if('textContent' in tControl)
        {
            tControl.textContent = iValue;
        }else if('innerHTML' in tControl)
        {
            tControl.innerHTML = iValue;
        }
    }

    // Get
    this.mGet = function()
    {
        // Resultaat aanmaken
        var tResult = null;

        // Afhankelijk van aanwezige property waarde instellen
        if('value' in tControl)
        {
            tResult = tControl.value;
        }else if('innerText' in tControl)
        {
            tResult = tControl.innerText;
        }else if('textContent' in tControl)
        {
            tResult = tControl.textContent;
        }else if('innerHTML' in tControl)
        {
            tResult = tControl.innerHTML;
        }

        // Resultaat teruggeven
        return tResult;
    }
}