var timer_id; 
function scroll_iframe(frm,inc,dir) { 
if (timer_id) clearTimeout(timer_id); 
if (window.frames[frm]) { 
if (dir == "v") window.frames[frm].scrollBy(0, inc); 
else window.frames[frm].scrollBy(inc, 0); 
timer_id = setTimeout("scroll_iframe('" + frm + "'," + inc + ",'" + dir + "')", 20); 
} 
} 

function stopScroll() { if (timer_id) clearTimeout(timer_id); }