Forloops作業

Question

我是一名11年級的學生，需要我的老師指定的forloop作業幫助。

代碼的問題在於輸出帖子，但它在消失前僅出現幾毫秒。

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; 
 
}

<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>

Answer 1

發生了什麼事是，因爲你放置在一張表格的一切，你的按鈕都有一個「提交」類型，瀏覽器嘗試「提交」你的表格。由於您沒有設置目標或方法，因此實際上只是刷新頁面。

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> 

沒有窗體標籤應該給你你想要的結果。