The processing method of different browser JavaScript variable scopes _javascript tips

1. About prototype: Here prototype is a feature of JavaScript, not the famous prototype framework:

<script type= "Text/javascript" > var string= "Hello World"; try{alert (String.phone ()); }catch (e) {alert (e);} String.prototype.phone=function () {return "159-10957151"; Alert (String.phone ()); </script>
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2. About variable scope, and Ie,firefox to JS different processing, here are a few examples, there are a few are originally seen from elsewhere in the notes, and some of my own dug out.
2.1

<script type= "Text/javascript" > var deep_thought = {the_answer:42, ask_question:function () {return this.the _answer; } }; var the_meaning = deep_thought.ask_question (); alert (the_meaning); </script>
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2.2

<script type= "Text/javascript" > Function Test_this () {return this; var i_wonder_what_this_is = Test_this (); alert (i_wonder_what_this_is); Result: [Object window]; </script>
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2.3:

<script type= "Text/javascript" > Function Click_handler () {alert (this);//Popup Window object} </script> ... <button id= ' Thebutton ' onclick= ' Click_handler () ' >click me!</button>
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2.4

<script type= "Text/javascript" > Function Click_handler (obj) {alert (obj); Result:[object Htmlbuttonelement]} </script> <button id= ' Thebutton ' onclick= ' Click_handler ' (this) ' > Click me!</button>
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2.5

<button id= ' Thebutton ' onclick= ' Click_handler (this) ' >click me!</button> <script-type= ' text/ JavaScript "> Function bigcomputer (answer) {this.the_answer = answer; This.ask_question = function () {alert (this.the_answer); The function addhandler () {var deep_thought = new Bigcomputer (), The_button = document.getElementById (' Thebutton ') ; The_button.onclick = deep_thought.ask_question; } window.onload = addhandler; result [undefined] </script>
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2.6

<button id= ' Thebutton ' onclick= ' Click_handler (this) ' >click me!</button> <script-type= ' text/ JavaScript "> Function bigcomputer (answer) {var self=this; Self.the_answer = answer; Self.ask_question = function () {alert (self.the_answer); The function addhandler () {var deep_thought = new Bigcomputer (), The_button = document.getElementById (' Thebutton ') ; The_button.onclick = deep_thought.ask_question; } window.onload = addhandler; result [</script>]
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2.7

<button id= ' Thebutton ' onclick= ' Click_handler (this) ' >click me!</button> <script-type= ' text/ JavaScript "> Function Btn_click () {alert (this); Function AddHandler () {The_button = document.getElementById (' Thebutton '); The_button.onclick = Btn_click; } window.onload = addhandler; result [undefined] </script>
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2.8

<button id= ' Thebutton ' onclick= ' Click_handler (this) ' >click me!</button> <script-type= ' text/ JavaScript "> Function Real_func () {alert (this); function Btn_click () {settimeout (real_func,100); Function AddHandler () {The_button = document.getElementById (' Thebutton '); The_button.onclick = Btn_click; } window.onload = addhandler; result [undefined] </script>
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2.9

<button id= ' Thebutton ' onclick= ' Click_handler (this) ' >click me!</button> <script-type= ' text/ JavaScript "> Function.prototype.bind = function (obj) {var method = this, temp = function () {return method.apply (o BJ, arguments); }; return temp; var real_func=function () {alert (this); function Btn_click () {settimeout Real_func.bind (this), 100); Function AddHandler () {The_button = document.getElementById (' Thebutton '); The_button.onclick = Btn_click; } window.onload = addhandler; result [undefined] </script>
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2.10

<script>//** variables need to be defined alert (document); [Object HTMLDocument] Alert (window.document); [Object HTMLDocument] Alert (window.face); Pretty var face= "pretty"; alert (face); Pretty alert (window.face); Pretty alert (Window.sock); Undefined alert (sock); Error:sock Not defined </script>
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2.11

<script type= "Text/javascript" > Function method () {var window={}; alert (window.location); alert (window.location); Method (); alert (window.location); </script>
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2.12

<script type= "Text/javascript" > var window={};//error: illegal Assignment! This works in Ie,but throw a Exception in Firefox alert (window.location); </script>
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2.13

<script type= "Text/javascript" >/** This is a very annoying code to disable alert/window.alert ("Hello World"); Window.alert=function (str) {document.write (str); }; Alert ("Hello World"); Window.alert ("Hello World"); </script>
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2.14:

Notice how the results of these three HTML files are different.
A.html:

<script type= "Text/javascript" > Alert (sock); Function sock () {alert ("function sock executed!"); alert (sock); </script>
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B.html:

<script type= "Text/javascript" > Alert (sock); var sock=function () {alert ("function sock executed!"); alert (sock); </script>
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C.html:

<script type= "Text/javascript" >//here does not pop "undefined"//a bit eccentric ah! alert (sock); </script>
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2.15

Look at the difference in how the Ie,firefox are run:

<script type= "Text/javascript" > Object.prototype.hello=function () {alert ("Hello"); } Window.hello (); </script>
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