i followed the following tutorial: https://www.windowsazure.com/en-us/develop/nodejs/tutorials/website-with-Mongodb-(mac)/

and executed app.js just as the tutorial said but i got:

No data received Unable to load the webpage because the server sent no data.

I was wondering what does the tutorial mean by:

You must replace the connection string above with the connection string for the MongoDB server you created earlier. For example, mongodb://mymongodb.cloudapp.net/tasks.

Thanks.

The error you received means "there is no connectivity between your node.js application and MongoDB server". This tutorial has a very important step to install MongoDB as below:

Create a virtual machine and install MongoDB

• This tutorial assumes you have created a virtual machine in Windows Azure. After creating the virtual machine you need to install MongoDB on the virtual machine:
• To create a Linux virtual machine and install MongoDB, see Installing MongoDB on a Linux Virtual machine.

So if you have completed above steps you must have created your MongoDB installed Virtual Machine DNS name as "Your_MongoDB_VM_name.cloudapp.net", if not please finish this step.

So if you have installed MongoDB on Linux Virtual Machine and if your DNS name is "Your_MongoDB_VM_name.cloudapp.net then in App.js you will change the following line as beow:

var taskList = new TaskList('mongodb://Your_MongoDB_VM_name.cloudapp.net/tasks');

The above change will let your Node.js application to connect with MongoDB server running on Linux machine and this change must needed in your node.js application to work.