how to create record using soap in dynamics crm 2013

i tried the below code in dynamics crm online 2013.

function new_record()
{
debugger;
var firstname = "srini";
var lastname = "hsk";
var donotbulkemail = "true";
var address1_stateorprovince = "CHD";
var address1_postalcode = "160036";
var address1_line1 = "#1429/2";
var address1_city = "Chandigarh";
var authenticationHeader = GenerateAuthenticationHeader();

// Prepare the SOAP message.
var xml = "<?xml version='1.0' encoding='utf-8'?>" +"<soap:Envelope xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'" +" xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'" +" xmlns:xsd='http://www.w3.org/2001/XMLSchema'>" +
authenticationHeader +"<soap:Body>" +"<Create xmlns='http://schemas.microsoft.com/crm/2007/WebServices'>" +"<entity xsi:type='contact'>" +"<address1_city>" + address1_city + "</address1_city>" +"<address1_line1>" + address1_line1 + "</address1_line1>" +"<address1_postalcode>" + address1_postalcode + "</address1_postalcode>" +"<address1_stateorprovince>" + address1_stateorprovince + "</address1_stateorprovince>" +"<donotbulkemail>" + donotbulkemail + "</donotbulkemail>" +"<firstname>" + firstname + "</firstname>" +"<lastname>" + lastname + "</lastname>" +"</entity>" +"</Create>" +"</soap:Body>" +"</soap:Envelope>";
// Prepare the xmlHttpObject and send the request.
var xHReq = new ActiveXObject("Msxml2.XMLHTTP");
xHReq.Open("POST", "/mscrmservices/2007/CrmService.asmx", false);
xHReq.setRequestHeader("SOAPAction", "http://schemas.microsoft.com/crm/2007/WebServices/Create");
xHReq.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
xHReq.setRequestHeader("Content-Length", xml.length);
xHReq.send(xml);
// Capture the result
var resultXml = xHReq.responseXML;

// Check for errors.
var errorCount = resultXml.selectNodes('//error').length;
if (errorCount != 0) {
    var msg = resultXml.selectSingleNode('//description').nodeTypedValue;
    alert(msg);
}
}

could you anybody clarify me

hsk srinivas