why don't I see any network call in Chrome's DevTools (or any other tool such as Charles)

Question

while yahoo finance updates stock price on an already open page such as http://finance.yahoo.com/q?s=AMRC

Thanks in advance! Jack M

Answer 1

The Yahoo stock page streams data to the client using a hidden IFRAME that streams data endlessly on a single chunked HTTP connection.

In Fiddler, you'll see this request with a URL like: http://streamerapi.finance.yahoo.com/streamer/1.0?s=AMRC,USD=X&o=JCI,^DJI,^IXIC,^GSPC,^TNX,^VIX,^RUT,EURUSD=X,AMRC,MSFT,PRGS,FB,DATA,GOOG,AMD,AAPL,BABA,AKAM,INTC,TSLA,AIG,ARMH,F&k=a00,a50,b00,b60,c63,c85,c86,g53,h53,j10,l84,l86,p20,p43,t53,t54,v53&j=c63,j10,l84,p20,p43,t53&r=0&callback=parent.yfs_u1f&mktmcb=parent.yfs_mktmcb&gencallback=parent.yfs_gencb&region=US&lang=en-US&localize=0&mu=1&ts=1431634090166&dp=0

If you want to "peek" at the response data (which will never complete, since it's a stream) you can right-click the Session in Fiddler's Web Sessions list and choose the COMETPeek command.