gistfile1.js

function cursorToPosition(el, ndx)
{
    if (typeof el === 'string') { el = document.getElementById(el); } // DOM el or id
    ndx = isNaN(ndx) ? el.value.length : parseInt(ndx);               // end by default

    if (el.setSelectionRange) {
        el.focus();
        el.setSelectionRange(ndx, ndx);
    }
    else if (el.createTextRange) {
        var range = el.createTextRange();
        range.collapse(true);
        range.moveEnd('character', ndx);
        range.moveStart('character', ndx);
        range.select();
    }
}

function cursorToStart(el)
{
    cursorToPosition(el, 0);
}

function cursorToEnd(el)
{
    cursorToPosition(el);
}