Set Values of all Data Types using Web API in Dynamics CRM 2015/16

Create with all Data Type (Account) 

function AccountWithAllDT() {
    try {
        //declare variables
        var uri = null;
        var stringJSONAcc = null;
        var entityIdWithLink = null;
        var getEntityId = null;

        //create JSON object 
        var JSONAcc = {};

        //set fields using JSON object
        //Single line of text
        JSONAcc.name = "CompanyName Pvt. Ltd."; //Account Name
        
        //Option Set
        JSONAcc.accountcategorycode = "2" //Category : 1--> Preferred Customer, 2--> Standard

        //Two Options
        JSONAcc.donotsendmm = false;//Marketing Materials : 0-->False/Send, 1-->True/Do Not Send
        //Whole Number
        JSONAcc.numberofemployees = 151; //Number of Employees

        //Decimal Number
        JSONAcc.new_decimalnumber = 345.12; //Decimal Number (Custom Field) 

        //Lookup
        JSONAcc["transactioncurrencyid@odata.bind"] = "/transactioncurrencies(4e950855-9eb3-e511-80de-6c3be5a8ad10)"; //Currency

        JSONAcc["primarycontactid@odata.bind"] = "/contacts(DFE54660-37CD-E511-80DE-6C3BE5A831DC)" //Primary Contact

        //Currency
        JSONAcc.creditlimit = 15000; //Currency Limit

        //Date 
        JSONAcc.new_dateonly = new Date();//Date Only (Custom Field)

        //convert JSON object to string
        stringJSONAcc = JSON.stringify(JSONAcc);

        //url for ajax request to create account
        uri = Xrm.Page.context.getClientUrl() + "/api/data/v8.0/accounts";

        //ajax request to create account
        $.ajax({
            type: "POST",
            dataType: "json",
            contentType: "application/json; charset=utf-8",
            url: uri,
            data: stringJSONAcc,
            beforeSend: function (XMLHttpRequest) {
                XMLHttpRequest.setRequestHeader("Accept", "application/json");
                XMLHttpRequest.setRequestHeader("Content-Type", "application/json; charset=utf-8");
                XMLHttpRequest.setRequestHeader("Prefer", "odata.include-annotations=*");
            },
            //Success Callback Function
            success: function (data, textStatus, XMLHttpRequest) {
                //get Response from Created Record
                entityIdWithLink = XMLHttpRequest.getResponseHeader("OData-EntityId");

                //get EntityId from ResponseHeader of Created Record  
                getEntityId = entityIdWithLink.split(/[()]/);
                getEntityId = getEntityId[1];

                //Display Enttity ID of Created Record
                Xrm.Utility.alertDialog("Entity ID : " + getEntityId);
            },
            //Error Callback Function
            error: function () {
                Xrm.Utility.alertDialog("Something Wrong in Script POST...:(");
            }
        });
    } catch (e) {
        Xrm.Utility.alertDialog(e.message + "\n" + e.description);
    }
}

=================================================

create an Activity & set Activity Party



///------------ Create Phone Call Activity ----------

function PhoneCall() {
    try {
        //declare variables
        var phonecallId = null;
        var stringJSONPhone = null;
        var urlPhone = null;

        //create activity party collection
        var parties = [];

        //create JSON object 
        var JSONPhone = {};

        //set fields using JSON object
        //Single line of text
        JSONPhone["subject"] = "Test Phone Call"; //Subject

        //Single line of text & format of phone 
        JSONPhone["phonenumber"] = "9876543210"; //Phone Number

        //Multiple Line of Text
        JSONPhone["description"] = "Phone Call Activity for Testing Purpose only...!"; //Description

        //Date and Time
        JSONPhone["scheduledend"] = new Date(); //Due

        //Lookup
        JSONPhone["regardingobjectid_account@odata.bind"] = "/accounts(B386D403-F7AD-E511-80DC-A45D36FC4F90)"; //Regarding is an account

        //ActivityParty (From)
        var sender = {};
        sender["partyid_systemuser@odata.bind"] = "/systemusers(D949B11D-9240-4037-8379-F31C7A36680E)";
        sender["participationtypemask"] = 1; //From

        //ActivityParty (To)
        var receiver1 = {};
        receiver1["partyid_account@odata.bind"] = "/accounts(B386D403-F7AD-E511-80DC-A45D36FC4F90)";
        receiver1["participationtypemask"] = 2; //To
        //receiver["addressused"] = "roohi@dyn20161.onmicrosoft.com";

        var receiver2 = {};
        receiver2["partyid_contact@odata.bind"] = "/contacts(DFE54660-37CD-E511-80DE-6C3BE5A831DC)";
        receiver2["participationtypemask"] = 2; //To

        var receiver3 = {};
        receiver3["partyid_lead@odata.bind"] = "/leads(ED81F0D9-37CD-E511-80DE-6C3BE5A831DC)";
        receiver3["participationtypemask"] = 2; //To

        //add this to collection
        parties.push(sender);
        parties.push(receiver1);
        parties.push(receiver2);
        parties.push(receiver3);

        //pass parties[] to phonecall_activity_parties
        JSONPhone["phonecall_activity_parties"] = parties;

        //Whole Number
        JSONPhone["actualdurationminutes"] = 25; //Duration

        //Two Options
        JSONPhone["directioncode"] = true;//Direction : 0-->False/Incomming, 1-->True/Outgoing

        //convert JSON object to string
        stringJSONPhone = JSON.stringify(JSONPhone);

        //url for ajax request to create phonecall activity
        urlPhone = Xrm.Page.context.getClientUrl() + "/api/data/v8.0/phonecalls";

        //ajax request to create phonecall activity
        $.ajax({
            type: "POST",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            url: urlPhone,
            data: stringJSONPhone,
            beforeSend: function (CreatePhoneCallActivityRequest) {
                CreatePhoneCallActivityRequest.setRequestHeader("Accept", "application/json");
                CreatePhoneCallActivityRequest.setRequestHeader("Content-Type", "application/json; charset=utf-8");
                CreatePhoneCallActivityRequest.setRequestHeader("Prefer", "odata.include-annotations=*");
                CreatePhoneCallActivityRequest.setRequestHeader("OData-MaxVersion", "4.0");
                CreatePhoneCallActivityRequest.setRequestHeader("OData-Version", "4.0");
            },
            //Success Callback Function
            success: function (data, taxtStatus, getPhoneCallActivityResponse) {
                //get Response from Created Record
                phonecallId = getPhoneCallActivityResponse.getResponseHeader("OData-EntityId");

                //get EntityId from ResponseHeader of Created Record 
                phonecallId = phonecallId.split(/[()]/);
                phonecallId = phonecallId[1];

                //Display Enttity ID of Created Record
                Xrm.Utility.alertDialog("Entity ID : " + phonecallId);

            },
            //Error Callback Function
            error: function (CreatePhoneCallActivityRequest, textStatus, errorThrown) {
                Xrm.Utility.alertDialog("Something Wrong in Script...:(");
            }
        });
    } catch (e) {
        Xrm.Utility.alertDialog(e.message + "\n" + e.description);
    }
}