Js代码，要求50以内加减乘除随机产生20题，带检验

<!doctype html>

<html>
    <head>
        <meta charset="utf-8">
        <script>
            var count = 0;
            var con;
 
            function getRandom() {
                return Math.floor(Math.random()*51);
            }
 
            function getOperator() {
                var arr = ['+', '-', '×', '÷'];
                return arr[Math.floor(Math.random()*arr.length)];
            }
 
            function validate(num1, op, num2) {
                if (op === '÷' && num2 === 0) return false;
                if (num1%num2 != 0) return false;
                if (op === '-' && num1 < num2) return false;
                 
                return true;
            }
 
            function create() {
                con = document.getElementById("content");
                var num1 = getRandom();
                var num2 = getRandom();
                var op = getOperator();
                var opTemp = op;
                if (op === '×') opTemp = '*';
                if (op === '÷') opTemp = '/';
                var answer = eval(num1 + (opTemp) + num2);
                 
                if(!validate(num1, op, num2)) return;
                 
                var str = num1 + " " + op + " " + num2 + " =" + " " + "<input type='text' style='width:30px;'/>";
                var newNode = document.createElement("div");
                newNode.className = "sss";
                newNode.setAttribute('data-answer', answer);
                newNode.style.width = "10px;";
                newNode.innerHTML = str;
                con.appendChild(newNode);
                 
                count ++;
            }
 
            function load() {
                while (count < 20) {
                    create();
                }
            }
             
            function getAnswer() {
                for (var i = 0, c = con.childNodes; i < c.length; i ++) {
                    if (c[i].className != 'sss') continue;
                 
                    var input = document.getElementsByTagName('input')[i-1];
                    var value = input.value;
                    if (c[i].getAttribute('data-answer') == value) {
                        input.style.backgroundColor = "green";
                    } else {
                        input.style.backgroundColor = "red";
                    }
                }
            }
        </script>
    </head>
    <body onload="load();">
        <div id="content">
        </div>
        <div>
            <button onclick="getAnswer();">提交</button>
            <button onclick="location = location;">重置</button>
        </div>
    </body>
</html>

posted on 2018-05-16 14:57  波Spirit  阅读(871)  评论(0)  编辑  收藏  举报

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