问题
I need to detect the first time a page loads in jQuery so that I can perform some actions only when the page loads the first time a user navigates to that page. Similar to server side code page.ispostbasck. I have tested $(document).ready and it fires every time the page loads so this will not provide what I need. I have also tried the jQuery Load function - it also fires every page load. So by page load an example is that I have an HTML input tag on the page of type button and it does not fire a postback (like an asp.net button) but it does reload the page and fires $(document).ready
Thanks
回答1:
You will have to use cookie to store first load information:
if (! $.cookie("cookieName")){
// do your stuff
// set cookie now
$.cookie("cookieName", "firstSet", {"expires" : 7})
}
Note: Above example uses jQuery Cookie plugin.
回答2:
An event doesn't exist that fires only when the page is loaded for the first time.
You should use jQuery's .ready() event, and then persist the fact that you've handled a first time page load using your method of choice (i.e. cookie, session variable, local storage, etc.).
Note: This method will never be fool proof unless you can store this information at the user level in a DB. Otherwise, as soon as the user clears their cookies, or whatever method you choose, the "first time loaded" code will fire again.
回答3:
I just ran into this problem and this is how I handled it. Keep track of the first time the page loads by using a variable initialLoad
:
var initialLoad = true;
$(document).ready(function() {
...
...
...
initialLoad = false;
});
Then in other functions, you can do this:
if (initialLoad) {
//Do work that is done when the page was first refreshed/loaded.
} else {
//Do work when it's not the initial load.
}
This works well for me. If the user is already on the page and some jQuery functions run, I now know if that user just loaded the page or if they were already on the page.
回答4:
The easy solution is to use jQuery ‘Once’ plugin
$(element).once('class-name', function() {
// your javascript code
});
来源:https://stackoverflow.com/questions/9485099/detect-first-page-load-with-jquery