There are 2 ways to call the option :
=IMPORTFROMWEB(data_sources, selectors, "jsRendering")
|3||=IMPORTFROMWEB(data_sources, selectors, A1:B1)|
You can also pair jsRendering with the timeToWait option. timeToWait is the time in seconds that the function will wait until it looks for the data. It can be useful in case the looked up data takes time to load.
Example: Wait for 10 seconds
=IMPORTFROMWEB(data_sources, selectors, "jsRendering, timeToWait:10")