<!DOCTYPE html>
<meta charset="utf-8">
<script>
    /* eslint-disable no-console */
    /* eslint-disable no-unused-expressions */
    "use strict";
    console.log(null);
    console.error("%ccolored message", "background:green; color:white");
    const obj = {
        testSymbol: Symbol("sym"),
        testobj: {},
        testnumber: 1,
        testArray: [1, {}, 2, 555],
        testUndf: undefined,
        testNull: null,
        testFunc() {},
        testString: 'string',
        prop1: 'prop1',
        prop2: 'prop2'
    };
    obj.c = obj;
    obj.prop3 = 'prop3';
    obj.prop4 = 'prop4';
    console.log(obj);
    const arr = [
        'string',
        {test: 'obj'},
        null,
        90,
        undefined,
        function() {},
        [1, {}, 2, 555]
    ];
    arr.push(arr);
    console.log(arr);
    document.access.non.existent.property.to.trigger.error;
</script>
<style>
  body {background: rgb(0, 128, 0);}
</style>
