Tabbing inside Textbox not working in chrome and safari

See more:

Javascript

Ajax

jQuery

Hi all

For tabbing i have written below code

function bindTabbing(event)
{
    if (event.which || event.keyCode)
    {
        // 9 indicates TAB key.
        if ((event.which == 9) || (event.keyCode == 9))
        {
            var subject = document.getElementById(txtProgramEditor); // Get the Editor textarea control.
            if (event.srcElement == subject) // If tab is pressed in the textarea then do the action.
            {
                // Creates a range and adds the Tab equivalent character in the text range.
                subject.selection = document.selection.createRange();
                subject.selection.text = String.fromCharCode(9);
                event.returnValue = false;
            }

            if (subject.selectionStart || subject.selectionStart == '0')
            {
                var str = subject.value;
                var startIndex = subject.selectionStart;
                subject.value = str.substring(0, startIndex) + '    ' + str.substring(startIndex, str.length);
                subject.focus();
                subject.selectionEnd = startIndex + 4;
                return false;
            }
        }
    }
    else
    {
        return true;
    }
}

this is working fine in FireFox and IE but not working in Chrome and Safari

Please locate the problem done by me or suggest what to do..

Thanks in advance.