No Syed, the SubReport is available in community version. It is one of the core feature. Only Inputs package in example is not in community version.
So basically, you set up a main report which in its view, there are two divs as you did. One of the div, you put your button and the second one you render a subreport. To update the sub report (on button click), you do:
subReport.update("content_subreport",{
"param":"any of your param",
});
Hope that helps.
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