alt Hacker Newsat the current technology we could cope with server generated old-school web pages because they would have low footprint, work faster and require less memory.
unless you have a high latency internet connection: https://news.ycombinator.com/item?id=44326816
however when you have a high latency connection, the "thick client" json-filled webapp will only have its advantages if the most of the business logic happens on the browser. I.e. Google Docs - great and much better than it used to be in 2000s design style. Application that searches the apartments to rent? Not really I would say.
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by the way in 2005 I programmed using very funny PHP framework PRADO that was sending every change in the UI to the server. Boy it was slow and server heavy. This was the direction we should have never gone...