* Clarify global scope

audreyt · audreyt · commit 7fd684ff8d1b · 2014-07-07T02:22:10.000+08:00
diff --git a/spreadsheet/chapter.md b/spreadsheet/chapter.md
@@ -329,7 +329,7 @@ There are three reasons for using a Web Worker to calculate formulas, instead of
 
 * While the worker runs in the background, the user is free to continue interacting with the spreadsheet, without getting blocked by computation in the main thread. 
 * Because we accept any JS expression in a formula, the worker provides a _sandbox_ that prevents formulas from interfering with the page that contains it, such as by popping out an `alert()` dialog.
-* A formula can refer to any coordinates as variables, which may contain yet another formula that possibly ends in a cyclic reference. To solve this problem, we use the Worker&rsquo;s _global scope_ self, and define these variables as _getter functions_ on its properties.
+* A formula can refer to any coordinates as variables, which may contain yet another formula that possibly ends in a cyclic reference. To solve this problem, we use the Worker&rsquo;s _global scope_ object `self`, and define these variables as _getter functions_ on `self` that contains the logic to mitigate cyclic references.
 
 With these in mind, let&rsquo;s take a look at the worker&rsquo;s code. Because **index.html** pre-loads the worker program with a `<script>` tag, in **worker.js** we first ensure that we&rsquo;re actually running as a background task:
 

-Original file line number
+Diff line change
 * While the worker runs in the background, the user is free to continue interacting with the spreadsheet, without getting blocked by computation in the main thread.
 * Because we accept any JS expression in a formula, the worker provides a _sandbox_ that prevents formulas from interfering with the page that contains it, such as by popping out an `alert()` dialog.
 -* A formula can refer to any coordinates as variables, which may contain yet another formula that possibly ends in a cyclic reference. To solve this problem, we use the Worker’s _global scope_ self, and define these variables as _getter functions_ on its properties.
 +* A formula can refer to any coordinates as variables, which may contain yet another formula that possibly ends in a cyclic reference. To solve this problem, we use the Worker’s _global scope_ object `self`, and define these variables as _getter functions_ on `self` that contains the logic to mitigate cyclic references.
 With these in mind, let’s take a look at the worker’s code. Because **index.html** pre-loads the worker program with a `<script>` tag, in **worker.js** we first ensure that we’re actually running as a background task: