Open Source Online EDA Simulator with limited feature 

1 EDA Playground gives engineers immediate hands-on exposure to simulating SystemVerilog, Verilog, VHDL, C++/SystemC, and other HDLs. All you need is a web browser. The goal is to accelerate learning of design/testbench development with easier code sharing and simpler access to EDA tools and libraries, you can access here  link

2 tutorial point verilog section , you can execute verilog code  link 

3 PCB Simulator, click here to run 

4 This is a simple web interface to run Verilog simulations using Icarus Verilog , click here to run