web3.js version 1.3.0 where the send function cannot be found, you can find a discussion of this in the web3.js repository: issue#3790, pr#3649, etc. this is usually displayed as the following error log:2.9.4 of the imToken App.web3.js, so we recommend that you upgrade or downgrade the web3.js package to fix this issue.web3.js API, so if you are still using such libraries, please package web3.js inside your web app yourself.