input box scroll to end of value with javascript

I have an html input box of type="text" that has a value assigned to it that exceeds the display width.  My goal is to have some javascript that can grab focus of the input box and scroll the cursor to the end of the input box value and allow the user to append to the current value.  I have used the following code to position the character at the end of the input box value and this seems to work ok in IE.  However, in FF and Safari, only the cursor moves to the specified location and the text inside the input box does not track to the new position.  Is there a way I can have the input box show the end of the string (similar to using the righ-arrow key on the keyboard to scroll to the end of the last character in the input box)?

function setCaretTo(pos) { 
	   var obj=document.getElementById('myInputBox');
    if(obj.createTextRange) { 
        /* Create a TextRange, set the internal pointer to
           a specified position and show the cursor at this
           position
        */ 
        var range = obj.createTextRange(); 
        range.move("character", pos); 
        range.select(); 
    } else if(obj.selectionStart) { 
        /* Gecko is a little bit shorter on that. Simply
           focus the element and set the selection to a
           specified position
        */ 
        obj.focus(); 
        obj.setSelectionRange(pos, pos); 
    } 
}

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