Clarify events, document extra vnode property

docs/hyperscript.md

@@ -181,7 +181,7 @@ Mithril does not attempt to add units to number values.
 
 ### Events
 
-Mithril supports event handler binding for all DOM events, including events whose specs do not define an `on${event}` property, such as `touchstart`
+Mithril supports event handler binding for all DOM events, using `addEventListener` under the hood to add events in case they don't have a corresponding `on${event}` property, such as the native `touchstart` or third-party events like Bootstrap's `show.bs.modal`.
 
 ```javascript
 function doSomething(e) {
@@ -191,6 +191,38 @@ function doSomething(e) {
 m("div", {onclick: doSomething})
 ```
 
+You may access the element itself through `this` like so, which is useful for things like form validation:
+
+```javascript
+function submit(e) {
+	this.validate()
+	m.request("api/form-endpoint", {
+		method: "POST",
+		data: new FormData(this),
+		background: true
+	})
+	.then(function () {
+		m.route.set("/form-submit")
+	})
+}
+
+m("form", {onsubmit: submit}, [
+	// ...
+])
+```
+
+It also provides access to the event's own literal vnode via `vnode`, so you may easily access its `attrs` and `children` through it, from an external function.
+
+```javascript
+function handleClick(e, vnode) {
+	vnode.attrs.context.validateValue(this.value)
+}
+
+m("div", [
+	m("input", {type: "text", context: this, onclick: handleClick})
+])
+```
+
 ---
 
 ### Properties