PlayPause song in the same button in adobe animate?

hello there 

i want to make a play/pause button

the same button for two functions

i am using this code...

import flash.events.MouseEvent;

stop();

start_button.addEventListener (MouseEvent.CLICK, onClick);

function onClick(event:MouseEvent):void

{

nextFrame(); // if you want to go to frame 2 and stop

play(); // if you want to go to frame 2 and play

}

it works for playing but not for pausing........

whats the action script for playpause in the same button?

anybody help me