TronLink, similar to MetaMask, is a bridge for allowing TRON DApps to run in the browser without having to deploy a TRON Full Node. If a user has TronLink already installed in the Chrome extension, then TronLink injects a version of TronWeb into every browser page. This allows for the web DApp to interact with the TRON network.
TronWeb interacts with the DApp as such:
If a user does not have TronLink or a similar application installed, then they most likely also don't have TronWeb in the browser when they use your web DApp. In this case, you can write a function that checks for tronWeb in the window object, and defines the HTTP ports for the user. The function can be written as below:
window.onload = function() {
if (!window.tronWeb) {
const HttpProvider = TronWeb.providers.HttpProvider;
const fullNode = new HttpProvider('https://api.trongrid.io');
const solidityNode = new HttpProvider('https://api.trongrid.io');
const eventServer = 'https://api.trongrid.io/';
const tronWeb = new TronWeb(
fullNode,
solidityNode,
eventServer,
);
window.tronWeb = tronWeb;
}
};