Forloops Assignment

Question

我是一名11年级学生，需要我老师指定的forloop作业的帮助。

代码的问题在于输出发布，但它在消失之前只出现了几毫秒。

＆＃13;

＆＃13;

function loops1() {
  var inputV = document.getElementById('input1').value;
  var inputINT = parseInt(inputV);
  var show = "";
  try {
    if (inputV == "") throw "is empty";
    if (isNaN(inputV)) throw 'must be a number';
  } catch (err) {
    alert("Input field " + err);
    return;
  }
  for (var i = 1; i <= inputINT; i++) {
    show += i + '<br>';
  }
  document.getElementById('showN').innerHTML = 'Numbers in order from 1 to n:' + '<br>' + show;
}

function loops2() {
  var inputV = document.getElementById('input2').value;
  var inputINT = parseInt(inputV);
  var sum = 0;
  try {
    if (inputV == "") throw "is empty";
    if (isNaN(inputV)) throw 'must be a number';
  } catch (err) {
    alert("Input field " + err);
    return;
  }
  for (var i = 1; i <= inputINT; i++) {
    sum += i;
  }
  document.getElementById('showN').innerHTML = 'Sum of numbers from 1 to n:' + '<br>' + sum;
}

function loops3() {
  var inputV = document.getElementById('input3').value;
  var inputINT = parseInt(inputV);
  var sumE = 0;
  try {
    if (inputV == "") throw "is empty";
    if (isNaN(inputV)) throw 'must be a number';
  } catch (err) {
    alert("Input field " + err);
    return;
  }
  for (var i = 1; i <= inputINT; i++) {
    if ((i % 2) == 0) sumE += i;
  }
  document.getElementById('showN').innerHTML = 'Sum of even numbers from 1 to n:' + '<br>' + sumE;
}

function loops4() {
  var inputV = document.getElementById('input4').value;
  var inputINT = parseInt(inputV);
  var factorial = 1;
  try {
    if (inputV == "") throw "is empty";
    if (isNaN(inputV)) throw 'must be a number';
  } catch (err) {
    alert("Input field " + err);
    return;
  }
  for (var i = 1; i <= inputINT; i++) {
    factorial = factorial * i;
  }
  document.getElementById('showN').innerHTML = 'Factorial of n:' + '<br>' + factorial;
}

function loops5() {
  var sports = ["Cricket", "Volleyball", "Basketball", "Hockey", "Soccer", "Football"];
  var sportsD = "";
  var lenA = sports.length
  for (var i = 0; i < lenA; i++) {
    sportsD += sports[i] + '<br>';
  }
  document.getElementById('showN').innerHTML = 'List of Sports:' + '<br>' + sportsD;
}

＆＃13;

<h1>LOOPS</h1>
<form>
  Write all numbers between 0 and input<br>
  <input type='text' id='input1' placeholder='enter number'><br>
  <button onclick='loops1()' type='submit'>Submit</button><br><br> Write sum of numbers 1 to input<br>
  <input type='text' id='input2' placeholder='enter number'><br>
  <button onclick='loops2()' type='submit'>Submit</button><br><br> Write sum of even numbers from 1 to input<br>
  <input type='text' id='input3' placeholder='enter number'><br>
  <button type='submit' onclick='loops3()'>Submit</button><br><br> Write factorial of input<br>
  <input type='text' id='input4' placeholder='enter number'><br>
  <button type='submit' onclick='loops4()'>Submit</button><br><br>
  <button type='button' onclick='loops5()'>Display Array</button>
</form>
<div id='showN'></div>

＆＃13;

＆＃13;

＆＃13;

Answer 1

发生了什么，因为你把所有东西放在一个表格中，而你的按钮都有一个＆＃34;提交＆＃34;类型，浏览器正在尝试提交＆＃34;你的表格。由于您没有设定目标或方法，因此只需刷新页面即可。

  Write all numbers between 0 and input<br>
  <input type='text' id='input1' placeholder='enter number'><br>
  <button onclick='loops1()'>Submit</button><br><br> Write sum of numbers 1 to input<br>
  <input type='text' id='input2' placeholder='enter number'><br>
  <button onclick='loops2()'>Submit</button><br><br> Write sum of even numbers from 1 to input<br>
  <input type='text' id='input3' placeholder='enter number'><br>
  <button onclick='loops3()'>Submit</button><br><br> Write factorial of input<br>
  <input type='text' id='input4' placeholder='enter number'><br>
  <button onclick='loops4()'>Submit</button><br><br>
  <button onclick='loops5()'>Display Array</button>

如果没有表单标签，则应该为您提供所需的结果。