Electronic waste, electricity consumption and greenhouse gas emissions
Choose a web host that combines economical servers with renewable energy, and which offsets its greenhouse gas emissions. The six criteria to bear in mind are:
1. WEEE (Waste Electrical and Electronic Equipment) management 2. Data center energy efficiency 3. Sustainable purchasing policy 4. Corporate social responsibility policy 5. Renewable energy power supplies 6. Carbon offset

Accessing the DOM (Document Object Model) via JavaScript is a heavy process that uses a lot of processor power (CPU). Minimize this type of access as much as possible.
To do so, you can assign a node to variables that you will repeatedly use in the application’s lifecycle, which avoids traversing the tree each time the document is manipulated.
Libraries such as ‘Shadow DOM’ can also be used to optimize the tree though a batch system.