ESP8266 Community Forum

Hello, I am new to this Esp8266, I have no prior knowledge in networking/wifi, but I have worked in Arduino and other controllers. I would like to develop a room temperature monitor with esp8266. The output temperature should be displayed in my computer as a widget. I'll explain the concept here. Please bear my English, also give suggestion or correct me if i am wrong.

Concept:
1. The device should run on esp-01 with a temp sensor, a battery and sleep mode.
2. The device should able to take periodical data (means should have sleep mode, right?)
3. The Temperature and battery value should be accessible through a HTML page.
4. The values from that html page should be fetched and displayed as a widget.

Problems I am facing:
1. I am not sure, how the esp works as a html server, at the same time connects to another AP to provide the data which is be accesible through internet. (Am I correct?).
2. How to read the battery value?
3. How to make the esp to sleep mode? if it is in sleep mode how a html server will work?
4. Here is the Quest!, I need the device should able to give data through my internet, if wifi-AP and internet is available. If internet is not available, my PC's wifi should automatically connect to the html server and able to fetch the data.

Once again, please correct me If my understanding is wrong and help me in this Quest!, Thanks.