I would like to know what are the exact differences between the way we embed report susing HTTP based way vs embedding by visualize.js.
Is there any performance issue? I stil see its taking time to load when used using visualize.js.
If you mean difference between using "iframe" and Visualize.js, the main difference is Visualize.js uses <div> tags instead of <iframe>. As such, it's possible to add effects like in the following page (in Japanese). Try dragging reports from the top to one of the three boxes at the bottom. Drag the report around. Try stretching the report by dragging the triangle at the bottom right hand side of the boxes.
Another difference may be that Visualize.js may be using async processing while the regular JasperReports Server uses sync processing. Sync processing slows down the server very much when under heavy load (i.e. large report generation, many users).