What is a hidden field in html? how to use?

HTML is the basis of web development. It has many elements and attributes, one of which is a very practical attribute is the "hidden field". Hidden fields come in handy when we need to pass values ​​in a web page but don't want these values ​​to be seen or modified by users.

1. What is a hidden field

In HTML, we can use the input tag to create a "hidden field". A hidden field is a special type of input box whose type attribute is set to "hidden", which means that the input box is invisible. Therefore, the user cannot see, modify, or enter anything, but we can get and process the values ​​on the server side.

2. The role of hidden fields

1. Passing parameters

In web development, we sometimes need to pass some parameters between pages, such as the user's ID or identifier of an operation, etc. At this time, it is very convenient to use hidden fields. You only need to put these parameters in the hidden fields, and you can obtain these values ​​​​through the POST or GET method in the background, thereby realizing data transfer between pages.

2. Prevent duplicate submission

In front-end development, sometimes users need to fill in some forms and submit them to the server, such as user registration or online shopping. However, some users may click the "Submit" button frantically, causing the server to receive multiple identical requests, causing the problem of data being repeatedly submitted. Using hidden fields can solve this problem very well. We can set up a hidden field in the form and set its value to a random number. When the user submits the form, we can check the uniqueness of this random number on the server side and reject the request if it is duplicated.

3. Information Security

Some web pages involve users’ personal privacy or sensitive information, such as passwords or ID numbers, etc. If this information is directly transmitted to the server in clear text, there will be a risk of being maliciously captured or intercepted. The use of hidden fields can solve this problem very well. We can put these sensitive information in the hidden field and encrypt it using an encryption algorithm, so that even if it is maliciously intercepted, the user's sensitive information cannot be easily stolen.

3. Use of hidden fields

The method of creating a hidden field is very simple. We only need to add an input input box in HTML and set its type attribute to "hidden". . The following is a simple example:

<input type="hidden" name="user_id" value="12345" />

In this example, we set up a hidden field whose name attribute is "user_id" and the value is "12345". In the background, we can obtain this value through the POST or GET method and process it accordingly.

Of course, in actual development, there are many advanced uses of hidden fields, such as dynamic generation using JavaScript, automatic hiding using third-party tool libraries, etc. But in any case, it is a very practical and commonly used technology that is worthy of our in-depth study and mastery.

In short, the hidden domain of HTML provides a very powerful solution for data transfer between pages, information security, and prevention of repeated submissions. It is an indispensable tool for us.

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