What is ECMAScript and why is it important?

In one sentence, ECMAScript for the JavaScript developer is like the Java Specification for the Java Developer.

In your development you have to decide which version of ECMAScript target, we suggest that you monitor the ECMA implementation status with websites like https://kangax.github.io/compat-table/es5/

Each Runtime environment can have a different level of implementation of the features of a defined specification.

At the time of writing this post ECMAScript 2015 is the ‘standard’ for the web browser e.g.:

Remember: In JavaScript you can develop using an ECMAScript version different to the ECMAScript version of the target.

To convert your code you need a Transpiler. We will write an article about it.