Solidity Events Example 1

pragma solidity ^0.4.0;

contract Receipt {
    event DepositLog(
        uint _value
        bytes32 indexed _id,
        address indexed _from,
    );

    function depositFunc(bytes32 _id) payable {
        // All calls directed at that function, including deeply nested
        // are going to be detected by the JavaScript API via 
        // filtering for `DepositLog` to be called.
        DepositLog(msg.sender, _id, msg.value);
    }
}