JavaScript 数据类型转换

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  JavaScript 数据类型转换表

  下表显示了将不同的JavaScript值转换为Number，String和Boolean的结果：

  原始值	转换为Number	转换为String	转换为Boolean
  false	0	"false"	false
  true	1	"true"	true
  0	0	"0"	false
  1	1	"1"	true
  "0"	0	"0"	true
  "1"	1	"1"	true
  NaN	NaN	"NaN"	false
  Infinity	Infinity	"Infinity"	true
  -Infinity	-Infinity	"-Infinity"	true
  ""	0	""	false
  "20"	20	"20"	true
  "twenty"	NaN	"twenty"	true
  [ ]	0	""	true
  [20]	20	"20"	true
  [10,20]	NaN	"10,20"	true
  ["twenty"]	NaN	"twenty"	true
  ["ten","twenty"]	NaN	"ten,twenty"	true
  function(){}	NaN	"function(){}"	true
  { }	NaN	"[object Object]"	true
  null	0	"null"	false
  undefined	NaN	"undefined"	false

  注意：引号（""）中的值表示字符串值。在红色的值是程序员可能不希望被转换为的值。

  有关JavaScript类型转换的教程，请阅读我们的JavaScript类型转换教程。