# Is it necessary to use local web servers for development?

**URL:** <https://discourse.threejs.org/t/is-it-necessary-to-use-local-web-servers-for-development/12243>\
**Category:** Questions\
**Tags:** dev-tools\
**Created:** [January 21, 2020, 9:13am UTC](https://discourse.threejs.org/t/is-it-necessary-to-use-local-web-servers-for-development/12243 "2020-01-21T09:13:12Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![anon81599084](https://avatars.discourse-cdn.com/v4/letter/a/34f0e0/32.png) [@anon81599084](https://discourse.threejs.org/u/anon81599084)\
**Post date:** [January 21, 2020, 9:13am UTC](https://discourse.threejs.org/t/is-it-necessary-to-use-local-web-servers-for-development/12243/1 "2020-01-21T09:13:12Z")

</div>

I execute my program most of the time with the Microsoft Edge Browser, because it needs a server to run my selfcoded webapps on chrome or firefox…  
Error in Chrome:  
Access to script at ‘file:/// jsm/loaders/PLYLoader.js’ from origin ‘null’ has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https.  
This is one of 40 errors. on Apache server it runs successfully.

That is the reason i test my code with edge because i dont need a server to run the app.  
Now i included loading draco files with dracoloader and got this error in edge:  
SCRIPT438: Object doesn’t support property or method ‘finally’  
I tried executing the dracoloader three.js example and same error appears, so i noticed after searching in the web, that it is a problem with Edge.  
How do other people work with three.js? Just running a server every time?

---

<div class="post-metadata">

**Author:** ![Sarge](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/sarge/32/23494_2.png) [@Sarge](https://discourse.threejs.org/u/Sarge)\
**Post date:** [January 21, 2020, 10:15am UTC](https://discourse.threejs.org/t/is-it-necessary-to-use-local-web-servers-for-development/12243/2 "2020-01-21T10:15:18Z")

</div>

Hi @anon81599084 I use a trick to emulate server to get passed CORS issue. If you have `python` you can try this in a `.bat` file to start your project. With this, you can run your three.js project in chrome, or changing the `.exe` name with any other browser. Run this file where your `index.html` is.

```
start chrome.exe http://localhost:7000
python -m http.server 7000

```

Also must comment for some reason, edge is very very slow compared to other browsers when I try running my threejs project.

---

<div class="post-metadata">

**Author:** ![Mugen87](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/mugen87/32/5645_2.png) [@Mugen87](https://discourse.threejs.org/u/Mugen87)\
**Post date:** [January 21, 2020, 10:38am UTC](https://discourse.threejs.org/t/is-it-necessary-to-use-local-web-servers-for-development/12243/3 "2020-01-21T10:38:10Z")

</div>

> [@anon81599084](#):
>
> How do other people work with three.js? Just running a server every time?

It’s definitely recommended to use a local server. There is actually a whole guide about this topic:

[https://threejs.org/docs/index.html#manual/en/introduction/How-to-run-things-locally](https://threejs.org/docs/index.html#manual/en/introduction/How-to-run-things-locally)