function aaa() {
var a = b =10;
}
console.log(a); /!*报错*!/
console.log(b); /!*无var提升至全局 10*!/
console.log(c);//undefind
var c = 10;// 变量的提升相当于在顶部var c;
var name="haha";
function changeName() {
console.log(name); /!*undefind 局部变量的提升*!/
var name="haha";
}
//++和--在后先赋值在自增减
//++和--在前先自增减在赋值
var num1 = 5;
var num2 = num1++;
//num1 = 6; num2 = 5
var num1 = 5;
var num2 = num1--;
//num1 = 4; num2 = 5
var num1 = 5;
var num2 = ++num1;
//num1 = 6; num2 = 6
var num1 = 5;
var num2 = --num1;
//num1 = 4; num2 = 4
//--和++效果一样
js变量提升问题,赋值和自增减的优先级问题
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转载自blog.csdn.net/qq_37744648/article/details/88884896
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