How to change window.location.href in JavaScript and then execute more JS?

window.location.href = base_url + "main"; <- when you load this page, call your code defined at ///next

you will have to add some parameters:

window.location.href=base_url+"main?parameter=true";

The other way would be to load the page with ajax into a div in the html.

Have a look at $.ajax() from jQuery.

please try to write

window.location.href = base_url + "main";

just before the end of if condition or use

setTimeout('window.location.href=base_url+"main"', 2000);

As already been noticed, you cant execute code after you went to another page

What you can do is to create redirector function, that will pass your function in cookie and ,redirect and then eval it on next page. (with another call to that redirector on next page)

But you should be aware of number of issues

1) Packing. It is upon you to decide how you pack cookie.

2) Encription. If you pass non-packed OR non-encrypted cookie the "bad user" can pass some malware code inside that cookie.

3) You should have VERY, VERY good reasons to do it. This way is too complicated, hard to code, hard to maintain

Much better if you do additional server-side controls, save it somewhere and reload on next page with one more request.