Question

What is the use of beforeSend Function in jQuery Ajax?

How to use the jQuery function?

I am Using jQuery 1.6.0, and Using Jersey API (Restful Web services) on Server Side.

$.ajax({

    type: "GET",
    url:ajax_url,
    dataType: "json",
    contentType: "application/json",                    
    async: false,
    beforeSend: function (xhr){ 
xhr.setRequestHeader('Authorization', "Basic "+ btoa(username + ':' + password)); 
    },
    success:function(data){
        alert(data.groups);
    },
    error:function(xhr,err){
        console.log("readyState:"+xhr.readyState+"\nstatus: "+xhr.status)
        alert(xhr.responseText)
        alert("Service is not Available , Try it after Some time");
    }
});

Java Code :

@GET

@Produces(MediaType.APPLICATION_JSON)

public String authCheck(){

return "({"groups": "success"})";

}

Whenever I am sending for authentication I am getting success response.

How to use beforeSend function and does we need to do any thing on server side?

Answer 1

Generally beforeSend() is used to do some stuff before actually send AJAX request like set Custom header and etc…

but your need is different that you want to authenticate user before your ajax call than

create one another function which give you User is authenticated or Not in Response
suppose this function is checkAuth();

so use

type: "GET",
    url:ajax_url,
    dataType: "json",
    contentType: "application/json",                    
    async: false,
    beforeSend:checkAuth,

.
.
.