> As for misspelling field names, the same is true for variable names in both languages, and many things in many languages.

No. This code causes an error in PHP:

    $name = 'John';
    echo $nmea; // error
    class A { public $name; }
    $a = new A;
    echo $a->nmea; // error

This code doesn't raise an error in JS:

    var a = { name: 'John'; };
    doSomething(a.nmea);  // no error

So with JS you learn about errors later and spend more time on debugging.