Notes from Javascript in 10 mins

• You won’t run into any trouble if you always end lines with semicolons.
• Every function returns a value.If you don’t use a return statement, then your function returns undefined
• Be careful how you define a variable. Always use var keyword
• Lazy scoping and mutability. The simplest way to fix this is to wrap our assignment in an anonymous
  function that is evaluated immediately, introducing another layer of scope.
• Never use the == operator unless you really want this behavior, x == null might be an exception
• Boxed values are always truthy and can store properties. Unboxed values will
  silently fail to store properties 
• All HTML objects, whether or not they’re somehow native, will be boxed.
• Throwing things - throw new Error(3)
• Implied global variables should never be used
• In JavaScript blocks do not have scope. Only functions have scope. Do not use blocks except as required by the compound statements.  
• The eval function is the most misused feature of JavaScript. Avoid it.
• The eval function has aliases. Do not use the Function constructor. Do not pass strings to setTimeout or setInterval.