- Prefer const and shorthand in docs

Author: brettz9

README.md

@@ -47,8 +47,8 @@ The jqXHR object is stored in element <em>data</em>-cache with the <code>jqxhr</
 call. It can be accessed like this:
 
 ````javascript
-var form = $('#myForm').ajaxSubmit({ /* options */ });
-var xhr = form.data('jqxhr');
+const form = $('#myForm').ajaxSubmit({ /* options */ });
+const xhr = form.data('jqxhr');
 
 xhr.done(function() {
 ...
@@ -216,14 +216,14 @@ URL to which the form data will be submitted.
 Serializes the form into a query string. This method will return a string in the format: `name1=value1&name2=value2`
 
 ````javascript
-var queryString = $('#myFormId').formSerialize();
+const queryString = $('#myFormId').formSerialize();
 ````
 
 ### fieldSerialize
 Serializes field elements into a query string. This is handy when you need to serialize only part of a form. This method will return a string in the format: `name1=value1&name2=value2`
 
 ````javascript
-var queryString = $('#myFormId .specialFields').fieldSerialize();
+const queryString = $('#myFormId .specialFields').fieldSerialize();
 ````
 
 ### fieldValue