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Q&A JavaScript redirect is getting "hijacked" and it is not onbeforeunload event.

My redirect in javascript somehow gets "hijacked" and I don't understand how. Previous developer (who is no longer working with the company) on page load initialized onbeforeunload event like so: ...

1 answer · posted 9mo ago by Vanity Slug ❤️‭ · last activity 7mo ago by Vanity Slug ❤️‭

Question javascript redirect

#4: Nominated for promotion by

Alexei‭ · 2023-08-09T04:41:13Z (9 months ago)

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#3: Post edited by

Vanity Slug ❤️‭ · 2023-08-08T15:49:34Z (9 months ago)
Add more debugging info.

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My redirect in javascript somehow gets "hijacked" and I don't understand how.
Previous developer (who is no longer working with the company) on page load initialized `onbeforeunload` event like so:
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
```
Now I have a requirement where I need to do a redirect, like so:
```
window.location = "https://duckduckgo.com"; // just some external url
```
Both pieces of code above are being reused by multiple pages. In all pages redirect works, **except one**. Only on 1 page after my debugger
steps over my redirect and then reaches this point
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
--> }
```
I do a step over and instead of getting redirected to `https://duckduckgo.com` I get redirected to a different internal page in my application.
Looks like something is happening in javascript between `onbeforeunload` and my redirect but I can't understand what it is. I don't even understand how I can continue debugging this.
**- How is that possible?**
**- What can I do to debug this farther?**
**- Is there some kind of `onbeforebeforeunload` event or something?**
---
**Update**.
"onbeforeunload" and "redirect" snippets of code are located in two different files, kind of like so:
File A.js:
```
$(function(){
...
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
...
});
```
File B.js
```
var Obj1 = (function(){
return {
init(): function() {
this.Obj2.init();
}
}
});
Obj1.Obj2 = (function(){
var process = function(){
...
window.location = "https://duckduckgo.com";
...
}
return {
run: process,
init: function(){
...
}
}
});
```
and then at some point process function gets called:
```
Obj1.Obj2.run();
```
**Update 2**:
I put `debugger;` in and out of every single piece of code where I saw "beforeunload" like so in my entire project:
```
$(this).on("beforeunload", function(){
...
});
```
~~Not a single breakpoint got hit.~~

My redirect in javascript somehow gets "hijacked" and I don't understand how.
Previous developer (who is no longer working with the company) on page load initialized `onbeforeunload` event like so:
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
```
Now I have a requirement where I need to do a redirect, like so:
```
window.location = "https://duckduckgo.com"; // just some external url
```
Both pieces of code above are being reused by multiple pages. In all pages redirect works, **except one**. Only on 1 page after my debugger
steps over my redirect and then reaches this point
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
--> }
```
I do a step over and instead of getting redirected to `https://duckduckgo.com` I get redirected to a different internal page in my application.
Looks like something is happening in javascript between `onbeforeunload` and my redirect but I can't understand what it is. I don't even understand how I can continue debugging this.
**- How is that possible?**
**- What can I do to debug this farther?**
**- Is there some kind of `onbeforebeforeunload` event or something?**
---
**Update**.
"onbeforeunload" and "redirect" snippets of code are located in two different files, kind of like so:
File A.js:
```
$(function(){
...
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
...
});
```
File B.js
```
var Obj1 = (function(){
return {
init(): function() {
this.Obj2.init();
}
}
});
Obj1.Obj2 = (function(){
var process = function(){
...
window.location = "https://duckduckgo.com";
...
}
return {
run: process,
init: function(){
...
}
}
});
```
and then at some point process function gets called:
```
Obj1.Obj2.run();
```
**Update 2**:
I put `debugger;` in and out of every single piece of code where I saw "beforeunload" like so in my entire project:
```
$(this).on("beforeunload", function(){
...
});
```
Not a single breakpoint got hit.
---
**Update 3**.
I added the following lines of code prior to redirect:
```
window.onunload = function(){
debugger; // Not hit
};
window.onbeforeunload = function(){
debugger; // <-- Hit 1st
};
$(window).on("beforeunload", function() {
debugger; // <-- Hit 2nd
});
$(window).on("unload", function() {
debugger; // Not hit
});
window.location = "https://<url>";
```
As comments above describe, first `window.onbeforeunload` gets hit, then `$(window).on("unload"...` and then redirect to **internal** <small>(not the one that I need)</small> page happens.

#2: Post edited by

Vanity Slug ❤️‭ · 2023-08-07T15:29:41Z (9 months ago)
Update with more details..

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My redirect in javascript somehow gets "hijacked" and I don't understand how.
Previous developer (who is no longer working with the company) on page load initialized `onbeforeunload` event like so:
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
```
Now I have a requirement where I need to do a redirect, like so:
```
window.location = "https://duckduckgo.com"; // just some external url
```
Both pieces of code above are being reused by multiple pages. In all pages redirect works, **except one**. Only on 1 page after my debugger
steps over my redirect and then reaches this point
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
--> }
```
I do a step over and instead of getting redirected to `https://duckduckgo.com` I get redirected to a different internal page in my application.
Looks like something is happening in javascript between `onbeforeunload` and my redirect but I can't understand what it is. I don't even understand how I can continue debugging this.
**- How is that possible?**
**- What can I do to debug this farther?**
**- Is there some kind of `onbeforebeforeunload` event or something?**

My redirect in javascript somehow gets "hijacked" and I don't understand how.
Previous developer (who is no longer working with the company) on page load initialized `onbeforeunload` event like so:
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
```
Now I have a requirement where I need to do a redirect, like so:
```
window.location = "https://duckduckgo.com"; // just some external url
```
Both pieces of code above are being reused by multiple pages. In all pages redirect works, **except one**. Only on 1 page after my debugger
steps over my redirect and then reaches this point
```
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
--> }
```
I do a step over and instead of getting redirected to `https://duckduckgo.com` I get redirected to a different internal page in my application.
Looks like something is happening in javascript between `onbeforeunload` and my redirect but I can't understand what it is. I don't even understand how I can continue debugging this.
**- How is that possible?**
**- What can I do to debug this farther?**
**- Is there some kind of `onbeforebeforeunload` event or something?**
---
**Update**.
"onbeforeunload" and "redirect" snippets of code are located in two different files, kind of like so:
File A.js:
```
$(function(){
...
window.onbeforeunload = function() {
if(<some condition>)
<make some ajax request>
}
...
});
```
File B.js
```
var Obj1 = (function(){
return {
init(): function() {
this.Obj2.init();
}
}
});
Obj1.Obj2 = (function(){
var process = function(){
...
window.location = "https://duckduckgo.com";
...
}
return {
run: process,
init: function(){
...
}
}
});
```
and then at some point process function gets called:
```
Obj1.Obj2.run();
```
**Update 2**:
I put `debugger;` in and out of every single piece of code where I saw "beforeunload" like so in my entire project:
```
$(this).on("beforeunload", function(){
...
});
```
Not a single breakpoint got hit.

#1: Initial revision by

Vanity Slug ❤️‭ · 2023-08-07T13:39:08Z (9 months ago)

Copy Link

Raw

Markdown

JavaScript redirect is getting "hijacked" and it is not onbeforeunload event.

My redirect in javascript somehow gets "hijacked" and I don't understand how.

Previous developer (who is no longer working with the company) on page load initialized `onbeforeunload` event like so:

```
window.onbeforeunload = function() {
    if(<some condition>)
        <make some ajax request>
}
```

Now I have a requirement where I need to do a redirect, like so:

```
window.location = "https://duckduckgo.com"; // just some external url
```

Both pieces of code above are being reused by multiple pages. In all pages redirect works, **except one**. Only on 1 page after my debugger 
 steps over my redirect and then reaches this point 

```
    window.onbeforeunload = function() {
        if(<some condition>)
            <make some ajax request>
--> }
```

I do a step over and instead of getting redirected to `https://duckduckgo.com` I get redirected to a different internal page in my application.

Looks like something is happening in javascript between `onbeforeunload` and my redirect but I can't understand what it is. I don't even understand how I can continue debugging this.

**- How is that possible?**

**- What can I do to debug this farther?**

**- Is there some kind of `onbeforebeforeunload` event or something?**

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