Manipulating URL parameters

I am new in JS, I am writing some extra filters on the Interface. So extra filter needs to add or update the parameter in the URL.

Option 1. No parameter in existing URL:

url = https://custom.net/

We want to add new parameter in the URL where key issector and value is IndependentConsultingDoctors

Output will be: https://custom.net/?sector=IndependentConsultingDoctors

Option 2. Update value in parameter of existing URL

URL = https://custom.net/?filter=title&sector=1234&sortby=1&page=1

We want to update parameter in the URL where key issector and value is IndependentConsultingDoctors

Output will be: URL = https://custom.net/?filter=title&sortby=1&page=1&sector=IndependentConsultingDoctors

Option 3. Delete and add parameter:

URL = https://custom.net/?filter=title&reportype=1234&sortby=1&page=1

We want to add new parameter in the URL where key issector and value is IndependentConsultingDoctors and delete reportype and inspectiontype parameters.

Output will be: URL = https://custom.net/?filter=title&sortby=1&page=1&sector=IndependentConsultingDoctors

The following is my code:

$(this).find('.btn').click(function(){  
    //var pathname = window.location.href;
    var pathname = "https://abc.com/?filter_by=title&filter_condition=&sector=1234&reportype=3455&sortby=1&page=1&itemperpage=10&input_list=&current_selected_option=2&masterfilter=%26itemperpage%3D10%26filter_by%3DAll%26filter_condition%3D%26sortby%3D1%26from_date%3D%26to_date%3D&from_date=&to_date="
    // Key and Value which need to add in paramaetrs  
    var key = "sector"
    var value = "Acutes";
    // Delete key from the parameters
    var delete_key = ["reportype", "inspectiontype"];

    // Split URL BASE and Get Parameters
    split_href = pathname.split("?");

    //No parameter present   
    if (split_href.length==1) {
         window.location.href = split_href[0]+'?'+key+'='+value;
    }else{
        // Create dictionary of parameter
        var para_dict = {};
        var para_list = split_href[1].split("&");
        for (ii in para_list){
            var tmp = para_list[ii].split("=");
            para_dict[tmp[0]] = tmp[1];
        }
        // Add target kay and Value
        para_dict[key] = value;

        // Delete key from the dinctionary
        for (ii in delete_key){
            delete para_dict[delete_key[ii]];       
        }
        //Create New Parameter string
        var new_para = "?";
        for (ii in para_dict){
            new_para = new_para+ii+"="+para_dict[ii]+"&";   
        }
        console.log(split_href[0]+new_para);
    }

});

Can you review my code and give me a more optimized solution?