Solution to JavaScript back button not working

In daily web development, we often encounter situations where we need to disable the back button of the page. This prevents users from using the browser's back function on web pages, thus protecting the security and stability of web pages. When using JavaScript to implement this function, we may encounter a situation where the back button is unavailable. Next, we'll explain how to solve this problem.

1. Cause of the problem

Disabling the browser's back button in JavaScript is usually achieved by operating the browser history. The back button will be disabled when executing the following two methods:

history.forward()
history.back()

However, in some cases, these methods are not able to disable the back button. Usually this situation occurs in the following two situations:

1. The current page is a form submitted through the HTTP POST method, and the form contains a large amount of data.
2. In the running environment of the web page, the code is executed so fast that when the history.forward() or history.back() method is executed, the browser does not respond to these operations in time.

2. Solution

For the above two situations, we can adopt the following solutions.

1. Realize the back function by modifying the URL

We can implement the back function by adding a specific identifier to the URL of the page. When the user clicks the back button, we only need to listen to the popstate event of the window object and determine whether the URL contains this identifier to determine whether the user needs to go back. The code is as follows:

window.addEventListener('popstate', function(event) {
    if (event.state && event.state.isBack) {
        // 执行后退操作
    }
});

var state = {
    isBack: true
};

history.pushState(state, '', '#back');

In the above code, we first listen to the popstate event of the window object. When the event is triggered, we determine whether the event.state object contains the isBack field. If it does, execute Back operation. When we need to disable the back button, we only need to call the history.pushState() method and add a state object with an identifier where it needs to be disabled.

2. Realize back by modifying the onbeforeunload method of the window object

We can also disable the back button by overriding the onbeforeunload method of the window object. When the user clicks the back button, because the onbeforeunload method is overridden, the browser will pop up a confirmation box. At this time, the user can only stay on the current page by selecting "Stay on this page" in the confirmation box. The code is as follows:

window.onbeforeunload = function() {
    return "是否离开当前页面？";
}

In the above code, we override the onbeforeunload method of the window object and return a confirmation box. When the user clicks the back button, the browser will pop up the confirmation box. Since the user can stay on the current page only by selecting "Stay on this page", the back button will become invalid.

Summary:

Disable the browser's back button. In some cases, you may encounter the problem that the back button is unavailable. We can solve this problem by modifying the URL or overriding the onbeforeunload method. When we need to disable the back button, we only need to call the corresponding method where it needs to be disabled.

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