<!DOCTYPE html><html> ???<head> ???????<meta charset="utf-8"> ???????<title></title> ???</head> ???<body> ???????<script type="text/javascript"> ???????????//全局变量和局部变量的区别/* ???????????function test(){ ???????????????var x=1; ???????????????alert(x); ???????????} ???????????test(); ???????????alert(x); ???//取不到变量，报错*/ ???????????function test(){ ???????????????y=5; ???????????????alert(y); ???????????}// ???????????test();// ???????????alert(y); ???????var x=1,y=2; ???????function calc(x,y){ ???????????document.write(‘a的值为‘+a+‘<br/>‘);//undefined ???????????document.write(‘函数体内x的值为：‘+x+‘<br/>‘); //1 ???????????document.write(‘函数体内y的值为：‘+y+‘<br/>‘); //2 ???????????var x=0,y=6; ???????????z=x+y; ???????????x=x+y; ???????????var a=198; ???????????document.write(‘a的值为：‘+a+‘<br/>‘); //198 ???????????document.write(‘x的值为：‘+x+‘<br/>‘); //6 ???????????return z; ???????} ???????//alert(calc(x,y)); ???????//alert(x+‘-‘+y+‘-‘+z); ???????var a=1,b=2; ???????function test1(){ ???????????var a=5,b=10; ???????????return a+b; ???????} ???????function test2(){ ???????????var a=11,b=22; ???????????return a+b; ???????} ???????alert(test1()); ???????alert(test2()); ???????alert(a+‘--‘+b); ???????????????????</script> ???</body></html>JS函数04
原文地址：https://www.cnblogs.com/f-z-g-boke/p/9545442.html