第五周作业（JavaScript）

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>判断是否为整数</title>
    <script>
        var n = 3.14;
        if (n%1==0)
        {
            document.write(n+ "是整数")
        }
        else
        {
            document.write(n + "是小数")
        }
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>水仙花</title>
    <script>
        var str = ""; 
        for (var i = 100; i < 1000; i++)
        {
            var a = i % 10;             
            var b = (i / 10) % 10;
            b = parseInt(b); 
            var c = i / 100;            
            c = parseInt(c);            
            if (i == (a * a * a + b * b * b + c * c * c)) 
            {
                str = str + i + "、";
            }
         }
         document.write("水仙花数有：" + str);
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8"/>
    <title>判断是否为闰年</title>
    <script>
        var a=2024;
        if((a%400==0)||(a%4==0&&a%100!=0))
            document.write(a+"是闰年");
        else
            document.write(a+"不是闰年");
    </script>
</head>
</html>

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8"/>
    <title>求出任意5个数的最大值</title>
    <script>
        var arr=[5,2,3,6,4];
        var max=-99999;
        for(var i=0;i<arr.length;i++){
            if(max<arr[i])
                max=arr[i];
        }
        document.write("最大值是"+max);
    </script>
</head>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>统计某一个字符的个数</title>
    <script>
        var str = "good good study,day day up";
        var n = 0;
        for(var i=0;i<str.length;i++)
        {
            var char = str.charAt(i);
            if (char.toLowerCase() == "o") {
                n++;
            }
        }
        document.write("字符串中含有" + n + "个字母o");
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>统计字符串中有多少个数字</title>
    <script>
        var str = "12aaaa 55bb5";
        var n = 0;
        for(var i=0;i<str.length;i++)
        {
            var char = str.charAt(i);
            if (char!=0 && !isNaN(char)) {
                n++;
            }
        }
        document.write("字符串中含有" + n + "个数字");
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>数组与字符串的转换操作</title>
    <script>
        var str1="我爱学习";
        var str2=str1.split("").join("><");
        var arr=str2.split("");
        arr.unshift("<");
        arr.push(">");    
        var result=arr.join("");
        document.write(result);
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>计算面积与体积，返回一个数组</title>
    <script>
        function get(a,b,c){
            var S = 2*(a*b+a*c+b*c);
            var V = a*b*c;
            var arr=[S,V];
            return arr;
        }
        var a=get(1,2,3);
        document.write("表面积为"+a[0]+"<br/>");
        document.write("体积为"+a[1]);
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>显示时间</title>
    <script>
        var d = new Date();
        var myYear=d.getFullYear();
        var myMonth=d.getMonth()+1;
        var myDay=d.getDate();
        var weekday=["日","一","二","三","四","五","六"];
        var myWeek=weekday[d.getDay()];
        document.write("今天是"+myYear+"年"+myMonth+"月"+myDay+"日"+" "+ "星期"+myWeek);
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>生成随机验证码</title>
    <script>
        var str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        var arr = str.split("");
        var result = "";
        for(var i=0;i<4;i++)
        {
            var n = Math.floor(Math.random() * arr.length);
            result += arr[n];
        }
        document.write(result);
    </script>
</head>
<body>
</body>
</html>

<!DOCTYPE html> 
<html lang="zh-CN">
<head>
    <meta charset="utf-8" />
    <title>生成随机颜色值</title>
    <script>
        var r = Math.floor(Math.random() * (255 + 1));
        var g = Math.floor(Math.random() * (255 + 1));
        var b = Math.floor(Math.random() * (255 + 1));
        var rgb = "rgb(" + r + "," + g + "," + b + ")";
        document.write(rgb);
    </script>
</head>
<body>
</body>
</html>