You can the MVC action from Javascript by sending an jQuery ajax request.
Change ShowSimple as ActionResult
public ActionResult ShowSimple()
{
ReportDocument reportdocument = new ReportDocument();
reportdocument.Load(Server.MapPath("~/") + "crystalreport.rpt");
var data=new {Status="Success"};
retunt JSon(data);
}
function Javascriptfunction()
{
$.getJSON('/Controller/ShowSimple/', function (data) {
alert(data);
});
}
function fnNext() {
var frm = document.forms[0];
frm.selecteditem.value = "Next";
Javascriptfunction();
return true;
}
Hope this helps