变量提高 做用域javascript
外部引用的函数做用域在外面。。。没法访问内部函数,能够经过参数添加 如(2)
var number =3; function getNumber() { return number; } var getNumber2 = (function(){ number =4; var number; number = number*2; return getNumber; })() alert(getNumber2()); alert(getNumber())
(2)
var number =3; function getNumber(nuber) { return number; } var getNumber2 = (function(){ number =4; var number; number = number*2; return getNumber(number); })() alert(getNumber2()); alert(getNumber())
var number =3; function getNumber() { return number; } var getNumber2 = (function(){ number =4; var number; number = number*2; return getNumber; function getNumber(){ return number; } })() alert(getNumber2()); alert(getNumber) 变量提高,覆盖