How to pass parameters in GET requests with jQuery

Question

How should I be passing query string values in a jQuery Ajax request? I currently do them as follows but I'm sure there is a cleaner way that does not require me to encode manually.

$.ajax({
    url: "ajax.aspx?ajaxid=4&UserID=" + UserID + "&EmailAddress=" + encodeURIComponent(EmailAddress),
    success: function(response) {
        //Do Something
    },
    error: function(xhr) {
        //Do Something to handle error
    }
});

I’ve seen examples where query string parameters are passed as an array but these examples I've seen don't use the $.ajax() model, instead they go straight to $.get(). For example:

$.get("ajax.aspx", { UserID: UserID , EmailAddress: EmailAddress } );

I prefer to use the $.ajax() format as it's what I’m used to (no particularly good reason - just a personal preference).

Edit 09/04/2013:

After my question was closed (as "Too Localised") i found a related (identical) question - with 3 upvotes no-less (My bad for not finding it in the first place):

Using jquery to make a POST, how to properly supply 'data' parameter?

This answered my question perfectly, I found that doing it this way is much easier to read & I don't need to manually use encodeURIComponent() in the URL or the DATA values (which is what i found unclear in bipen's answer). This is because the data value is encoded automatically via $.param()). Just in case this can be of use to anyone else, this is the example I went with:

$.ajax({
    url: "ajax.aspx?ajaxid=4",
    data: { 
        "VarA": VarA, 
        "VarB": VarB, 
        "VarC": VarC
    },
    cache: false,
    type: "POST",
    success: function(response) {

    },
    error: function(xhr) {

    }
});

Answer 1

Here is the syntax using jQuery $.get

$.get(url, data, successCallback, datatype)

So in your case, that would equate to,

var url = 'ajax.asp';
var data = { ajaxid: 4, UserID: UserID, EmailAddress: EmailAddress };
var datatype = 'jsonp';

function success(response) {
// do something here 
}

$.get('ajax.aspx', data, success, datatype)

Note $.get does not give you the opportunity to set an error handler. But there are several ways to do it either using $.ajaxSetup(), $.ajaxError() or chaining a .fail on your $.get like below

$.get(url, data, success, datatype)
 .fail(function(){
})

The reason for setting the datatype as 'jsonp' is due to browser same origin policy issues, but if you are making the request on the same domain where your javascript is hosted, you should be fine with datatype set to json.

If you don't want to use the jquery $.get then see the docs for $.ajax which allows room for more flexibility

Answer 2

The data property allows you to send in a string. On your server side code, accept it as a string argument name "myVar" and then you can parse it out.

$.ajax({
    url: "ajax.aspx",
    data: [myVar = {id: 4, email: 'emailaddress', myArray: [1, 2, 3]}];
    success: function(response) {
    //Do Something
    },
    error: function(xhr) {
    //Do Something to handle error
    }
});