How to verify that the password cannot be empty in javascript

As a basic technology for modern Web development, JavaScript is undoubtedly a must-have. In web development, form validation is an important but often overlooked part. In actual applications, user errors or malicious submissions often occur. At this time, we need to verify the input to ensure the accuracy and accuracy of form submission. safety.

In form verification, verifying whether the password is empty is a very basic verification. In this article, we will introduce how to use JavaScript to check whether the password in an input box is empty, and elaborate on the implementation process through sample code.

First of all, we need to make it clear that the way to implement JavaScript to verify whether the password is empty requires first obtaining the username element on the HTML page to read the password entered by the user. Here we can achieve this step by obtaining the corresponding elements on the page through document.querySelector. The specific code is as follows:

let inputPwd = document.querySelector('#password');

Next, we can use the trim method in JavaScript to remove the spaces in the user input and determine whether the password entered by the user is empty. The specific code is as follows:

let pwdValue = inputPwd.value.trim();

if (!pwdValue) {
  alert('对不起，密码不能为空！');
  return;
}

The above code implements the verification of whether the password is empty. If the user does not enter the password, a warning layer will pop up on the page to prompt the user to enter the password.

In order to combine all the verification logic, we can encapsulate it as a function for future code reuse. The specific implementation code is as follows:

function checkPwd() {
  let inputPwd = document.querySelector('#password');
  let pwdValue = inputPwd.value.trim();
  
  if (!pwdValue) {
    alert('对不起，密码不能为空！');
    return false;
  }
  
  return true;
}

We can use this function in other verification functions to verify passwords. For example, the following code implements verification of the entire form:

function checkForm() {
  let checkResult = true;
  
  checkResult = checkResult && checkUsername();
  checkResult = checkResult && checkPwd();
  
  return checkResult;
}

In In this method, we call the checkUsername and checkPwd functions to verify the username and password. If an error is detected and any verification function returns false, the entire form submission will not take effect.

To sum up, we can use JavaScript to verify whether the password is empty through the above methods. Of course, in the actual development process, other verification logic needs to be combined, such as password length, whether it contains special characters, etc. But first, we need to master the basic verification methods as a basis for further development.

Summary:

• JavaScript verifies that the password cannot be empty. You need to obtain the password element on the HTML page and remove possible spaces through the .trim method, and finally determine whether the password is null.
• In order to make the code easier to maintain and reuse, we need to encapsulate password verification as a function and can call it through other verification functions.
• In daily development, we also need to combine other verification logic to ensure the integrity and security of data.

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