Dynamically select the recordtype by custom javascript Button

When i tried to create a contact record without selection of record type it is not possible from the standard button. So i came up with some custom java script button.

To create a custom button navigate to Setup- Customize - Contacts - Buttons, Links, and Actions

Click on Buttons, Links, and Actions and click new Button or link. Give the Name and api name and select the Display Type as List Button, behavior as Execute javascript and content source as onclick javascript.

Paste the below code in the space provided. change the recordtype name to your record type name.

{!REQUIRESCRIPT("/soap/ajax/33.0/connection.js")} 
{!REQUIRESCRIPT("/soap/ajax/33.0/apex.js")} 

var qr = sforce.connection.query("SELECT Id FROM RecordType WHERE SobjectType ='" + "Contact" + "'" +" AND DeveloperName = '"+"RecordTypeName"+ "'"); 
var records = qr.getArray("records"); 

if(!records.isEmpty)
{ 
 var redirecturl="/003/e?retURL={!Account.Id}&con4={!Account.Name}&con4_lkid={!Account.Id}&RecordType="+qr.records.Id; 
 window.location=redirecturl; 
}

Create Sobject Records from JavaScript using Jsforce Library

Create a vf page and past the below code 

JSforce that you can easily run the SalesforceAPI from JavaScript

JSforce that can run easily the SalesforceAPI from JavaScript. It is very convenient to try using Visualforce page of Developer environment.

Download the jsforce jibrary and create in static resource with name jsforce
https://cdnjs.cloudflare.com/ajax/libs/jsforce/1.5.0/jsforce.js

<apex:page>
    <apex:includeScript value="{!$Resource.jsforce}" />
    <apex:form>
        <apex:commandButton value="Get Count" onclick="return doClick();" />
    </apex:form>
    <script>
        var conn = new jsforce.Connection({accessToken: '{!$Api.Session_Id}'});
        function doClick () {
            var soqlQuery = 'SELECT Id, Name FROM Account';
            conn.query (soqlQuery, function (err, res) {
                if (err) {
                    alert (err);
                }
                alert (res.records.length);
            });
            return false;
        }
    </script>
</apex:page>

How to access custom settings via JavaScript or Visual force page markup?

<apex:page >
<script type="text/javascript">
var url = "{!$Setup.MyCustomSet__c.URL__c}";
alert(url);
</script>
<apex:outputText value="{!$Setup.MyCustomSet__c.URL__c}"/>
</apex:page>