Salesforce Callout Functionality in Apex

function Callout(methodtype,endpoint)
{
var json = JSON.stringify(eval("(" + body+ ")"));
var b64Str = new sforce.Base64Binary(username + ':' + password);
var authStr = "Basic " + b64Str.toString();
var rallyHeader =
{
"Authorization": authStr,
"Content-Type":  "text/javascript",
};
var result = sforce.connection.remoteFunction( {
url:endpoint,
mimeType: "text/plain",
method:methodtype,
requestHeaders:rallyHeader,
requestData:json,
async: false,
onSuccess: function(response){alert(response);;},
onFailure: function(error) { alert(error);}});
}