How can JSL automatically stop the download of data stream data as Python does?

[#1]

Hello!

Data on this site will be updated every 3 seconds.Using the normal method, you will always be downloading without downloading data.
Python writes code like this to terminate the data download.
How to change this Python to JSL?

This address is captured after the packet.

http://16.push2.eastmoney.com/api/qt/stock/details/sse?fields1=f1,f2,f3,f4&fields2=f51,f52,f53,f54,f55&mpi=2000&ut=bd1d9ddb04089700cf9c27f6f7426281&fltt=2&pos=-0&secid=1.688686

http://16.push2.eastmoney.com/api/qt/stock/details/sse?fields1=f1,f2,f3,f4&fields2=f51,f52,f53,f54,f... 

[#2]

Just the data in front of the red box.
Null data is generated 3 seconds later.It's not necessary.

Thanks!

[#3]

The code will remain in download until it crashes.

u =
"http://16.push2.eastmoney.com/api/qt/stock/details/sse?fields1=f1,f2,f3,f4&fields2=f51,f52,f53,f54,f55&mpi=2000&ut=bd1d9ddb04089700cf9c27f6f7426281&fltt=2&pos=-0&secid=1.688686";
txt = Load Text File( u );
a = Length( txt );
P = "[{";
off1 = Contains( txt, P );
If( off1,
	tx = Substr( txt, off1, Length( txt ) )
);
Q = "}]";
off2 = Contains( tx, Q, -1 );
If( off2,
	tx = Substr( tx, 1, off2 + 1 )
);
b = Right( tx, 2 );
d1 = JSON To Data Table( tx );

[#4]

Open this way and press ESC repeatedly to get these results

[#5]

I think JSL sockets might work if you want to invest the time to learn about sockets and the http protocol. I think using curl from run program might also work, but I'm not sure how to terminate curl from run program.