I am trying to check if a variable is defined, if it is then an ajax request is run...If it is not I want the user to be redirected to a separate page where the variable is set.
for example I want something like this:
// if variable is undefined
if (typeof accessKey === 'undefined') {
alert('the variable is not set!');
} else {
var accessKey = 'some random string generated from google';
alert('the variable is set!');
proceed to refresh the page and run through check again.
}
So the first time the page is run, it checks if the variable is set. If the variable is not set it will set the variable and then reload the page and run through the check again.
Problem is 'accessKey' always returns undefined but the code runs through as if the variable is defined. Why?
If the variable is not set it will set the variable and then reload the page [emphasis mine] and run through the check again
There is your problem: variables (or any other piece of js code) do not persist between page reloads.
If you need stuff to persist, you have to use one of these:
Server-side sessions or databases (using ajax to pass data to the server and persist it there)
Client-side storage (such as localStorage).
Cookies (can be generated at client-side or server-side)
Save the value in hiddenfields or in cookie.
Related
I follow below code :
function My_Function() {
var x;
if (confirm("Exit?") == true) {
x = "Ok";
window.location.href = '#Url.Action("Login", "Account")';
Session.Abandon();
} else {
x = "Cancel";
}
}
I want to prevent is that , after logging out , then I click the back navigation button , I don't want to go back to the previous page.
Browsers can cache content locally. So no matter what you are doing on your server, after logging out, if the user clicks on the Back button, the browser can decide to get the last page from the local cache and display it.
In order to prevent this behavior you could serve all controller actions that require authentication with cache disabled. This can be achieved by decorating them with a custom [NoCache] filter. This filter will ensure that the proper response headers are set when serving actions that require authentication to prevent the browser from caching them.
This being said, please note that the Session.Abandon(); call should be done on your server - inside your Logout controller action that is supposed to clear the authentication cookies and session state.
Session.Clear and Session.RemoveAll are identical; the latter just calls the former. They immediately remove all items stored in the session, but the session itself survives. Session_OnEnd does not fire.
Session.Abandon doesn't actually clear the values immediately, it just marks the session to be abandoned at the end of the current request. You can continue to read the values for the rest of the request. If you write to the session later in the request, the new value will be quietly discarded at the end of the request with no warning. Session_OnEnd fires at the end of the request, not when Abandon is called.
I have a variable which is updated on every page shift, but I want to store the value in the first call for good somehow.
The variable is e.g
$sizeOfSearch = $value['HotelList']['#activePropertyCount'];
First time the page loads it's 933, on next page the same value is retrieved but it's now different e.g 845. This goes on page for page.
What I want is to store 933 for good. So I can show this number on every page.
Can I somehow store the first time this value is retrieved ? (I get the value via REST request)
Sessions maybe or ?
session_start() creates a session or resumes the current one based on a session identifier passed via a GET or POST request, or passed via a cookie.
When session_start() is called or when a session auto starts, PHP will call the open and read session save handlers. These will either be a built-in save handler provided by default or by PHP extensions (such as SQLite or Memcached); or can be custom handler as defined by session_set_save_handler(). The read callback will retrieve any existing session data (stored in a special serialized format) and will be unserialized and used to automatically populate the $_SESSION superglobal when the read callback returns the saved session data back to PHP session handling.
So, on every page make sure to start it with:
<?php
session_start();
Then, you set the value like this:
if(!isset($_SESSION['name'])) {
$_SESSION['name'] = $sizeOfSearch;
}
Whenever you need the retrieve the value use this:
print $_SESSION['name'];
This session will keep store the variable as long as you don't destroy it. Code for destroying a session:
session_destroy();
My project is composed by 2 html pages:
index.html, which contains the login and the registration form.
user_logged.html, which contains all the features of a logged-in user.
Now, what I want to do is a control if the user is really logged in, to avoid the case where a user paste a url in the browser and can see the pages of another user.
hours as now, if a user paste this url in the browser:
www.user_loggato.html?user=x#profile
is as if logged in as user x and this is not nice.
My html pages both use js files that contains scripts.
I decided to create a global variable called logged inizialized to false and change the variable to true when the login is succesful.
The problem is that the variable, remains false.
here is the code:
var logged=false; (write in the file a.js)
while in the file b.js I have:
function login() {
//if succesfull
logged=true;
window.location.href = "user_loggato.html?user="+ JSON.parse(str).username + #profilo";
Now with some alerts I found that my variable logged is always false. Why?
Javascript is not the way to go, as it runs on the client side. Even if there would be a way to share javascript variables between different requests, the user could manipulate them.
You have to take a server side technique for this (maybe PHP with sessions).
JS variables will reset on every submit/refresh. You could use sessionStorage or cookies for this purpose. For example:
Put this in your login form:
function login() {
window.sessionStorage[logged] = true;
window.location.href = "user_loggato.html?user="+ JSON.parse(str).username + #profilo";
}
And in your user_loggato.html, you can retrive it like:
function getLoginStatus() {
return window.sessionStorage['logged'];
}
Hope this helps.
I want to get the title of a webpage without opening it, i.e. without using window.open().
I basically want to check whether the page i am providing the link for exists or an error is returned.
What I am trying is checking for similar links. Here is the code
(I want to know when to break out of this loop, i.e. at what point the link I am writing exists).
document.getElementById("TOI").innerHTML="<p>";
if (month<10) var m="0"+month;
else var m=month;
for(var i=1;;i++){
alert("ji");
var a="http://epaper.timesofindia.com/Repository/CAP/"+year+"/"+m+"/"+date+"/CAP_"+year+"_"+month+"_"+date+"_"+i+".pdf";
alert(a);
var link=window.open(a);
window.focus();
alert(link.location);
alert(link.document.title);
if(link.document.title!="The page cannot be found"){
link.close();
document.getElementById("TOI").innerHTML=document.getElementById("TOI").innerHTML+"<a href='http://epaper.timesofindia.com/Repository/CAP/"+year+"/"+m+"/"+date+"/CAP_"+year+"_"+month+"_"+date+"_"+i+".pdf' target=_blank>Page "+i+"</a> ";
}
else{link.close();break;}
}
document.getElementById("TOI").innerHTML=document.getElementById("TOI").innerHTML+"<\p>";
}
See to check if a url exists or not, you must use a server-side scripting language. Javascript is client-side and can't access server. So, first of all make a server side script (maybe php) that returns the status of url that you wanna check. Then from javascript side, use an ajax call to get the result of that script. That way you can check your url array, if all of them exists or not.
var attribute = element.getAttribute("title");
I want to get title of a webpage
without opening it(that is without
using window.open()) I basically want
to check whether the page i am
providing the link for exists or an
error is returned
Just because a page has a title doesn't mean it exists.
http://www.google.com/thispagedoesnotexist.htm
Examine HTTP status codes rather than page titles:
Can Prototype or JQuery return an HTTP status code on an AJAX request
I need to enable a script which is present in a .net master page, in only selected html pages that use this master page. can this be achieved by declaring a variable in javascript of html pages where I need this script and set the variable to some value, so that I can enable the scripts in master page only when variable is NotNullorEmpty? Does some one know if this works. If so how to get javascript variable in html, in to .net master page ?
There are 2 ways I can think of.
The first if to assign the variable to a hidden input field. Which can be accessed in the Request.Form.
html
<input type="hidden" value="your value" name="Hidden1" id="Hidden1"/>
javascript
document.getElementById('Hidden1').value = "an other value";
C#
var myValue = Request.Form["Hidden1"];
The second is saving the variable into a cookie which can be accessed in Request.Cookies.
var myValue = Response.Cookies["Cookie1"].Value;
The most flexible form of this that I have seen is to render a JSON object directly to the page as script (adding any other script you might need also), then making the javascript code fill in a hidden field with JSON data on form submit for the server to parse.
Here are the basic steps:
Create an empty hidden field for the server to read when the client submits, but send it to the client empty.
Create a string which is the script and JSON data you need to send to the client. (Use the JavaScriptSerializer .NET class.)
Fill a LiteralControl with the script tag and its contents. (This works well in the OnPreRender step, but you can do it elsewhere.)
Include JSON2.js (it's all over the web - get it from a trusted source)
Write javascript code to fill the hidden field on submit, using JSON2.stringify() to push any javascript object into that field.
On the server, you can again use JavaScriptSerializer to read the values from the submitted object.
What you are basically wanting to do is test for javascript.
There are a few ways to do this, but I would use both a server-side and client-side cookie.
In your global.asax's onbeginrequest, test for a server-side cookie of "js-test-s"
Cookie Exists, check for "js-test-c"
"js-test-c" Cookie Exists, JS enabled
"js-test-c" No Cookie, JS disabled
Cookie doesn't exist...
Set the "js-test-s" cookie
output a simple html document...
[html]
[head]
[meta refresh tag set to 1 second /]
[script to set "js-test-c" cookie, then force refresh /]
[/head]
[body][/body]
[html]
Browser will refresh the request with one or both cookies set.
WARNING: You may want to store the original request details, and redirect to another location in case cookies are disabled.
I might be not understanding the question correctly but as far as I can tell the easiest way to do this is by creating a property on the master page and then setting it on all pages that need to execute the script:
In Master page
public bool EnableScript
{
set
{
if (value == true)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), "startup", "alert('test');", true);
}
}
}
In all pages that need to run javascript that use the current master page:
protected void Page_Load(object sender, EventArgs e)
{
this.Master.EnableScript = true;
}
If you have to output your JavaScript on every page, even on the once that don't execute it (why?) then just add it as a function and then inside your property add a code to call that function, and set your property to true on all pages that require JavaScript to execute.