SOURCE

//全局变量、局部变量
var globalVariable1 = 0;

function test1() {
    document.write(localVariable1+ "<br/>");
    var localVariable1 = 2;
    //打印globalVariable1
    document.write(globalVariable1 + "<br/>");

    //打印localVariable1
    document.write(localVariable1+ "<br/>");
}

//打印localVariable1
//document.write(localVariable1);

//打印globalVariable2
document.write(globalVariable2 + "<br/>");


test1();

var globalVariable2 = 1;

function test2() {
    var localVariable2 = 3;

    //打印localVariable1
    //document.write(localVariable1 + "<br/>");

}
test2();

//打印localVariable2
//document.write(localVariable2 + "<br/>");
//打印globalVariable1
document.write(globalVariable1 + "<br/>"); 
document.write("--------------------------------<br/>");


//表达式调用
function add(i,j) {
    var one = i + j;
    return one;
}
var a = add(1,2) + 3;
document.write(a+"<br/>");
document.write("--------------------------------<br/>");

//判断是否是闰年
function isLeapYear(year){
    if((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)){
        document.write(year+" is an leap year "+ "<br/>");
    }
    else{
        document.write(year+" is not a leap year "+ "<br/>");
    }
}
isLeapYear(2020);
isLeapYear(2000);
isLeapYear(2001);

document.write("--------------------------------<br/>");
//求出4个数中的最大值
function maxnum(a,b,c,d){
    var max=a;
    if(b>max){
        max=b;
    }
    if(c>max){
        max=c;
    }
    if(d>max){
        max=d;
    }
    return max;  
}
document.write("4个数中的最大值是：" + maxnum(1,7,11,10)+"<br/>");

document.write("--------------------------------<br/>");

//定义两个函数，分别求出任意五个数中的最大值和最小值
function maxNum(a,b,c,d,e){
    var max=a;
    if(b>max){
        max=b;
    }
    if(c>max){
        max=c;
    }
    if(d>max){
        max=d;
    }
    if(e>max){
        max=e;
    }   
    return max;  
}

function minNum(f,g,h,i,j){
    var min=f;
    if(g<min){
        min=g;
    }
    if(h<min){
        min=h;
    }
    if(i<min){
        min=i;
    }
    if(j<min){
        min=j;
    }   
    return min;  
}
document.write("5个数中的最大值是：" + maxNum(5,3,8,2,7)+"<br/>");
document.write("5个数中的最小值是：" + minNum(5,3,8,2,7)+"<br/>");