求助：实现按用户输入次数生成随机字符串的JavaScript程序

Hey there! I see your code got cut off mid-way, and that’s probably a big reason it’s not running. Let’s break down what’s missing and get your random string generator working perfectly.

First, let’s look at your original (truncated) code: #

function randomString() { 
  var totalIterations = parseInt(document.getElementById('input').value); 
  var output = document.getElementById('output'); 
  output.innerHTML = ''; 
  var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz"; 
  var string_length = 8; 
  var randomstri...

The main issues here: #

• Your code is incomplete—you started declaring randomstri but never finished the logic to build the string or loop through the requested iterations.
• There’s no loop to generate multiple strings based on the user’s input count.
• You aren’t validating the input (what if the user enters a non-number or negative value?).

Here’s the fixed, complete version: #

First, let’s include the full HTML structure to make this work end-to-end (you probably have this already, but it’s good to clarify):

<!-- HTML -->
<input type="number" id="input" placeholder="Enter number of strings" min="1">
<button onclick="randomString()">Generate Strings</button>
<div id="output"></div>

Now the updated JavaScript:

function randomString() { 
  // Get and validate user input
  var totalIterations = parseInt(document.getElementById('input').value); 
  var output = document.getElementById('output'); 
  output.innerHTML = ''; 

  // Handle invalid input to avoid errors
  if (isNaN(totalIterations) || totalIterations < 1) {
    output.innerHTML = '<p>Please enter a valid positive number!</p>';
    return;
  }

  var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz"; 
  var string_length = 8; 

  // Loop to generate the requested number of strings
  for (var i = 0; i < totalIterations; i++) {
    var randomString = '';
    // Build each individual 8-character random string
    for (var j = 0; j < string_length; j++) {
      var randomNum = Math.floor(Math.random() * chars.length);
      randomString += chars.substring(randomNum, randomNum + 1);
    }
    // Add each string to the output (with line breaks for readability)
    output.innerHTML += '<p>' + randomString + '</p>';
  }
}

Let’s walk through what’s added: #

1. Input Validation: We check if the input is a valid positive number—this stops errors from bad user input like letters or negative values.
2. Double Loop:
   • The outer loop runs exactly totalIterations times (once for each string you want to generate).
   • The inner loop builds each 8-character string by picking random characters from your chars set.
3. Clean Output: Each generated string is added to the output div with a paragraph tag, so they’re neatly separated and easy to read.

Just copy this code, and it should work exactly as you want—enter a number, click the button, and get that many random 8-character strings!

内容的提问来源于stack exchange，提问作者Tope Kenny