for/while

作者: Es__ | 来源:发表于2018-09-17 21:15 被阅读0次

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>while</title>
    <script>
        var moy = 1000;
        var n = 0;
        while(moy < 5000){
            moy += moy*0.05;
            n+=1;
        }
        alert(n+'年');
        

        do{
            var score = prompt('小明成绩：');
        }while(!(+score>=0&&+score<=100&&score!=''));
        
    </script>
</head>
<body>
    
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>for</title>
    <script>
        var sum = 0;
        for(var odd=1;odd < 100; odd++){
            if(odd%2!=0){
                sum+=odd;
            }
        }
        alert('1-100之间所有奇数之和:'+sum);
        

        var b7s = 0;
        var b7n = 0;
        for (var i = 1;i<100;i++) {
            if (i%7==0) {
                b7s+=i;
                b7n+=1;
            }
        }
        alert('1-100之间所有7的倍数的总和:'+b7s+'，1-100之间所有7的倍数的个数:'+b7n);
        

        for (var i=100; i<1000; i++) {
            var ge = i%10;
            var shi = (parseInt(i/10))%10;
            var bai = parseInt(i/100);
            if(ge**3+shi**3+bai**3==i){
                console.log('水仙花数:'+i);
            }
        }

        var iszhi = prompt('输入一个数：');
        if(!(+iszhi)|| iszhi=='' || +iszhi<2 || +iszhi!=parseInt(iszhi)){
                alert('输入有误。');
        }
        else{
            var flag=true;
            for (var i = 2; i < +iszhi/2; i++) {
                if (+iszhi%i==0) {
                    flag=false;
                }
            }
            if (flag){
                alert('是质数');
            }
            else{
                alert('不是质数');
            }

        }



        
        var str='';
        for (var i = 1; i <=9 ; i++) {
            for (var col = 1; col <= i; col++) {
                str += (col+'*'+i+'='+col*i+'  ');
            }
            str += '\n';
        }
        console.log(str);

        
        var zhi='';
        for (var i = 2; i <= 100; i++) {
            var flag=true;
            for (var b = 2; b <= i/2; b++) {
                if (i%b==0) {
                    flag=false;
                    break;
                }
            }
            if (flag){
                zhi += i+' ';
            }
        }
        console.log(zhi);

    </script>
</head>
<body>
    
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>计算器</title>
    <script>
        window.onload = function(){
            var num1 = document.getElementById('num1');
            var num2 = document.getElementById('num2');
            
            var sf = document.getElementById('sf');
            var btn = document.getElementById('btn');

            btn.onclick = function(){
                var val1 = num1.value;
                var val2 = num2.value;

                if(val1=="" || val2==""){
                    alert('输入框不能为空！');
                    return;
                }
                if(isNaN(val1) || isNaN(val2)){
                    alert('请输入数字！');
                    return;
                }
                switch(sf.value){
                    case '+':
                        alert((parseFloat(val1)*100 + parseFloat(val2)*100)/100);
                        break;
                    case '-':
                        alert((parseFloat(val1)*100 - parseFloat(val2)*100)/100);
                        break;
                    case '*':
                        alert((parseFloat(val1)*100) * (parseFloat(val2)*100)/10000);
                        break;
                    case '/':
                        alert((parseFloat(val1)*100) / (parseFloat(val2)*100));
                        break;
                }
            }
        }


    </script>
</head>
<body>
    <input type="text" id='num1' >
    <select id="sf">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select>
    <input type="text"  id="num2">
    <input type="button" id='btn' value="=">
    
</body>
</html>