Being a web developer , you must be at least one time used JQuery Ajax requests from your client end . And the growing popularity of HTML 5 demands more such calls . And the main headache occurs when you want to access some thing from server , which may be hosted in a different domain .
The commonly suggested solution to this problem is to use “JSONP” as data type in your Ajax request . Even though the same thing is repeated in all forums , but none clearly mentions what is JSONP and how you can implement it for cross domain – “GET” requests .
JSONP
JSONP is an addition JSON request ( JSON with Padding ) , it wraps JSON in a function call. For example, the following might be returned from the third-party server:
mycallback({"key" : "value"});
Code Snippet
In your regular JQuery Ajax Call , modify the “dataType “ Parameter to “jsonp” and add a new parameter called “jsonpCallback” . set the value to the call back function same as the one which you are going to specify in your server file. here in this example it is “mycallback” .
Your Script Would looking like the below
<script type="text/javascript">
var URL = "http://MyServer/OL/version.txt";
$.ajax(URL, {
crossDomain: true,
dataType: "jsonp",
jsonpCallback: mycallback,
success: function (data, text, xhqr) {
alert(data.text);
},
error: function (xhqr) {
console.log("Error");
}});
</script>
Now your client is ready to send and receive cross domain Ajax calls . Now we’ll have a look at your server side file from which you are returning some data to client side .
Now modify your server side file say for example “version.txt” as shown below .
mycallback({"text" : "Hello World This Text is from cross domain server "})
The above statement is a method which wraps your Json Data .
Happy Coding 
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