Clear all fields in a form upon going back with br

问题:

I need a way to clear all the fields within a form when a user uses the browser back button. Right now, the browser remembers all the last values and displays them when you go back.

More clarification on why I need this I\'ve a disabled input field whose value is auto-generated using an algorithm to make it unique within a certain group of data. Once I\'ve submitted the form and data is entered into the database, user should not be able to use the same value again to submit the same form. Hence I\'ve disabled the input field in the first place. But if the user uses the browser back button, the browser remembers the last value and the same value is retained in the input field. Hence the user can submit the form with the same value again.

What I don\'t understand is what exactly happens when you press the browser back button. It seem like the entire page is retrieved from cache without ever contacting the server if the page size is within the browser cache limit. How do I ensure that the page is loaded from the server regardless of browser setting when you press the browser back button?

回答1:

Modern browsers implement something known as back-forward cache (BFCache). When you hit back/forward button the actual page is not reloaded (and the scripts are never re-run).

If you have to do something in case of user hitting back/forward keys -- listen for BFCache pageshow and pagehide events.

A pseudo jQuery example:

$(window).bind(\"pageshow\", function() {
  // update hidden input field
});

See more details for Gecko and WebKit implementations.

回答2:

Another way without JavaScript is to use <form autocomplete=\"off\"> to prevent the browser from re-filling the form with the last values.

See also this question

Tested this only with a single <input type=\"text\"> inside the form, but works fine in current Chrome and Firefox, unfortunately not in IE10.

回答3:

I came across this post while searching for a way to clear the entire form related to the BFCache (back/forward button cache) in Chrome.

In addition to what Sim supplied, my use case required that the details needed to be combined with Clear Form on Back Button?.

I found that the best way to do this is in allow the form to behave as it expects, and to trigger an event:

$(window).bind(\"pageshow\", function() {
    var form = $(\'form\'); 
    // let the browser natively reset defaults
    form[0].reset();
});

If you are not handling the input events to generate an object in JavaScript, or something else for that matter, then you are done. However, if you are listening to the events, then at least in Chrome you need to trigger a change event yourself (or whatever event you care to handle, including a custom one):

form.find(\':input\').not(\':button,:submit,:reset,:hidden\').trigger(\'change\');

That must be added after the reset to do any good.

回答4:

If you need to compatible with older browsers as well \"pageshow\" option might not work. Following code worked for me.

$(window).load(function() {
    $(\'form\').get(0).reset(); //clear form data on page load
});

回答5:

This is what worked for me.

<script>
$(window).bind(\"pageshow\", function() {
    $(\"#id\").val(\'\');
    $(\"#another_id\").val(\'\');
});
</script>

I initially had this in the $(document).ready section of my jquery, which also worked. However, I heard that not all browsers fire $(document).ready on hitting back button, so I took it out. I don\'t know the pros and cons of this approach, but I have tested on multiple browsers on multiple devices, and no issues with this solution were found.

回答6:

Below links might help you..

Browser back button restores empty fields, Clear Form on Back Button?

Hope this helps... Best Luck