console 命令行工具 X clear

console

function writeDocument(variable) {
    document.write(variable + "<br/>");

} 
   function sum_all() 
        {
            var result = 0;
            for (var i = 0; i <= 100; i++) 
            {
                result += i;
            }
            return result;
        }
            var s = sum_all();

            writeDocument("for循环"+'<br/>'+"1+2+3+···+100="+'<br/>'+s);
            //方法二   while()循环
        function sum_all2() {
            var result2 = 0; var i = 0;
            while (i <= 100) 
            {
                result2 += i;
                i++;
            }
            return result2
            }
            var x=sum_all2();
           writeDocument("while循环"+'<br/>'+"1+2+3+···+100="+'<br/>'+x);
            // 方法三  do-while语句 

        function sum_all3() 
        {
            var result3 = 0; var i = 0; 
            do {
               
                result3 += i;
                 i++; 
            }

        while (i <= 100);

        return result3
        }
        var y=sum_all3();
         writeDocument("do while循环"+'<br/>'+"1+2+3+···+100="+'<br/>'+y);

<!DOCTYPE html><html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
    </body>
</html>