console 命令行工具 X clear

console

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/>")
//函数的调用
//在表达式中调用，一般用于“有返回值的函数”，
//然后函数的返回值会参与表达式的计算。
//定义函数
        function addSum(a, b) 
        {
            var sum = a + b;
            return sum;
        }
        //调用函数
        var n = addSum(1, 2) + 100;
        document.write(n+ "<br/>");

document.write("---------------------------------<br/>")
//判断是否是闰年
function isLeapYear(year) 
        {
            //判断闰年的条件
            if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)) 
            {
                return year + "year is an leap year";
            }
            else
            {
                return year + " is not a leap year";
            }
        }
        //调用函数
        document.write(isLeapYear(2022));
        document.write("---------------------------------<br/>")
        function writeDocument(variable) {
    document.write(variable + "<br/>");
} 

//求4个数中的最大值 
function getMax(a,b,c,d) {
            var maxNum;
            maxNum = (a > b) ? a : b;
            maxNum = (maxNum > c) ? maxNum : c;
            maxNum = (maxNum > d) ? maxNum : d;
            return maxNum;
        }
        document.write("5个数中的最大值为：" + getMax(7,16,50,-9));

//函数在超链接中的调用
<!DOCTYPE html> 
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
        function expressMes()
        {
            alert("很烦");
        }
    </script>
</head>
<body>
    <a href="javascript:expressMes()">wadada</a>
</body>
</html>