JavaScript Ninja Cheats study notes (a)

Client web application life cycle stages

• Page builder
  • Parse html code and build dom
  • JavaScript code execution
    • Global code and the function body
      • Different: different execution position, global function have JavaScript engine automatically executed in a direct way, the function code must be other code calls
        
• Event Processing
  • The browser execution environment core idea : the same time, only one piece of code execution, single-threaded execution model
  • Event queue: realization browser needs a way to track the incurred but not yet processed.
  • The reason register event handlers: the occurrence of an event is not the order of the law, you must tell the browser before the event is processed which event we have to deal with
  • Two ways to register the event:
    • By the function to a particular attribute
      Example: window.load = function(){}
      But there are disadvantages, you can only sign up for an event.
    • By using the built-addEventListener
      Example: document.body.addEventListener("mousemove",function(){ console.log("mousemove"); })
      You can register multiple events to an element, more commonly

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function

• The difference between functions and objects: function is callable
• How to determine an object is an object or function typeof abba === 'function'
• The callback function meaning : in the implementation process, we have established will be a function of other functions at a later point the right time to come back call
• The callback function uses:
  1. Storage function
  2. Since the memory function
• Function immediately: Why is wrapped in brackets: Reason purely syntactic level, in order to function declarations converted into a function expression
• Formal and actual parameters: ... arguments es6 parameter can be an expressionfunction(a,b=3)