jQuery.ajax() forced to explicitly set empty string value to data property

[Pavel-Mileshchenko]

correct example $J.ajax({

type: "POST", url : "challenge/delete.js", data: "", forced to explicitly set empty string value to prevent server side HTTPStatus::LengthRequired dataType: "script"

});

error example: lead to error HTTPStatus::LengthRequired in Webrick. Mongrel had exception. Not tested on Apache. $J.ajax({

type: "POST", url : "challenge/delete.js", dataType: "script"

});

[dmethvin]

Dup of #4044.