I am developing a broadcasting app using Eddystone. The question here is, as far as I know, there is no beacon broadcasting (TLM) API on the mobile web (in a browser such as Chrome). To make sure, I want to make sure that there is no such technology. Thank you.
The only platform that allows you to do this is the Chrome Browser on Chrome OS. On that platform, users can optionally enable BLE advertising in a browser setting, then apps can programmatically configure BLE advertising including for beacons like Eddystone. The folks at Radius networks put together a JavaScript Beacon Library to help you do this.
For all other platforms the answer is no, you cannot advertise BLE using a web browser. This answer applies to all other browsers on all other operating systems.
It is worth mentioning that Google sponsors the Web Bluetooth initiative to bring BLE support to browsers. However, it is designed to support only the BLE central role (not the peripheral role needed to advertise). And even Web Bluetooth's central support is very limited -- it doesn't support general BLE scanning for beacons (it only supports scanning for BLE services for connection purposes.) Further still, Web Bluetooth is not supported at all by Apple Safari on either iOS or MacOS, and Apple has said it does not plan to support it in the future.
Bottom line, if you want to work with beacons in the web browser, you are largely out of luck. The one exception is that you can advertise on ChromeOS.