Readme: Add note about trimming whitespaces inside required method

Arkni · staabm · commit d1090351e574 · 2017-07-09T21:42:00.000+02:00
diff --git a/README.md b/README.md
@@ -51,6 +51,24 @@ See the [Contributing Guidelines](CONTRIBUTING.md) for details.
 
 **IMPORTANT NOTE ABOUT EMAIL VALIDATION**. As of version 1.12.0 this plugin is using the same regular expression that the [HTML5 specification suggests for browsers to use](https://html.spec.whatwg.org/multipage/forms.html#valid-e-mail-address). We will follow their lead and use the same check. If you think the specification is wrong, please report the issue to them. If you have different requirements, consider [using a custom method](https://jqueryvalidation.org/jQuery.validator.addMethod/).
 In case you need to adjust the built-in validation regular expression patterns, please [follow the documentation](https://jqueryvalidation.org/jQuery.validator.methods/).
+**IMPORTANT NOTE ABOUT REQUIRED METHOD**. As of version 1.14.0 this plugin stops trimming white spaces from the value of the attached element. If you want to achieve the same result, you can use the [`normalizer`](https://jqueryvalidation.org/normalizer/) that can be used to transform the value of an element before validation. This feature was available since `v1.15.0`. In other words, you can do something like this:
+``` js
+$("#myForm").validate({
+	rules: {
+		username: {
+			required: true,
+			// Using the normalizer to trim the value of the element
+			// before validating it.
+			//
+			// The value of `this` inside the `normalizer` is the corresponding
+			// DOMElement. In this example, `this` references the `username` element.
+			normalizer: function(value) {
+				return $.trim(value);
+			}
+		}
+	}
+});
+```
 
 ## License
 Copyright &copy; Jörn Zaefferer<br>
