fix type fforget

Author: yangchuan

2-ui/2-events/01-introduction-browser-events/article.md

@@ -48,7 +48,7 @@ For instance, to assign a `click` handler for an `input`, we can use `onclick`,
 
 On mouse click, the code inside `onclick` runs.
 
-Please note that inside `onclick` we use single quotes, because the attribute itself is in double quotes. If we fforget that the code is inside the attribute and use double quotes inside, like this:  `onclick="alert("Click!")"`, then it won't work right.
+Please note that inside `onclick` we use single quotes, because the attribute itself is in double quotes. If we forget that the code is inside the attribute and use double quotes inside, like this:  `onclick="alert("Click!")"`, then it won't work right.
 
 An HTML-attribute is not a convenient place to write a lot of code, so we'd better create a JavaScript function and call it there.