1 files changed, 19 insertions, 12 deletions
diff --git a/javascript.html.markdown b/javascript.html.markdown
index c59a90c3..aabd5e43 100644
--- a/javascript.html.markdown
+++ b/javascript.html.markdown
@@ -39,13 +39,14 @@ doStuff()
 // 1. Numbers, Strings and Operators
 
 // JavaScript has one number type (which is a 64-bit IEEE 754 double).
-// As with Lua, don't freak out about the lack of ints: doubles have a 52-bit
-// mantissa, which is enough to store integers up to about 9✕10¹⁵ precisely.
+// Doubles have a 52-bit mantissa, which is enough to store integers
+//    up to about 9✕10¹⁵ precisely.
 3; // = 3
 1.5; // = 1.5
 
-// All the basic arithmetic works as you'd expect.
+// Some basic arithmetic works as you'd expect.
 1 + 1; // = 2
+0.1 + 0.2; // = 0.30000000000000004
 8 - 1; // = 7
 10 * 2; // = 20
 35 / 5; // = 7
@@ -77,13 +78,13 @@ false;
 !true; // = false
 !false; // = true
 
-// Equality is ==
-1 == 1; // = true
-2 == 1; // = false
+// Equality is ===
+1 === 1; // = true
+2 === 1; // = false
 
-// Inequality is !=
-1 != 1; // = false
-2 != 1; // = true
+// Inequality is !==
+1 !== 1; // = false
+2 !== 1; // = true
 
 // More comparisons
 1 < 10; // = true
@@ -97,11 +98,17 @@ false;
 // and are compared with < and >
 "a" < "b"; // = true
 
-// Type coercion is performed for comparisons...
+// Type coercion is performed for comparisons with double equals...
 "5" == 5; // = true
+null == undefined; // = true
 
 // ...unless you use ===
 "5" === 5; // = false
+null === undefined; // = false 
+
+// ...which can result in some weird behaviour...
+13 + !0; // 14
+"13" + !0; // '13true'
 
 // You can access characters in a string with charAt
 "This is a string".charAt(0);  // = 'T'
@@ -460,8 +467,8 @@ var myNumberObj = new Number(12);
 myNumber == myNumberObj; // = true
 
 // Except, they aren't exactly equivalent.
-typeof(myNumber); // = 'number'
-typeof(myNumberObj); // = 'object'
+typeof myNumber; // = 'number'
+typeof myNumberObj; // = 'object'
 myNumber === myNumberObj; // = false
 if (0){
     // This code won't execute, because 0 is falsy.