function textareaAutoHeightCountLines(textarea)
{
    var hard_lines = 1;
    var last = 0;

	text = textarea.value;

    while( true )
	{
        last = text.indexOf("\n", last+1);
        if( last == -1 )
			break;

        hard_lines ++;
    }

    return hard_lines;
}

function textareaAutoHeight(textarea)
{
    textarea.rows = textareaAutoHeightCountLines(textarea);
}