Send bitcoin raw transaction to network via webserver?
If you have a local bitcoin node (i.e. bitcoind running on the webserver), you can use the RPC command sendrawtransaction in order to send a transaction through your node to the network. Alternatively you can use a third party transaction broadcasting service like those offered by blockchain.info and blockcypher.com. Lastly, you could attempt to speak the Bitcoin P2P protocol and send the transaction directly to nodes on the network.