JavaScript 语法

<script type="text/javascript">
    var then = new Date(2011, 0.1);
    var later = new Date(2011, 0, 1, 17, 10, 30);
    var now = new Date();
    typeof (now + 1)
    typeof (now - 1)
    now ==now.toString()
    var elapsed = now - then;
    later.getFullYear();
    later.getMonth();
    later.getDate();
    later.getDay();
    later.getHours();
    later.getUTCHours();

    var s = "hello,world";
    s.charAt(0);
    s.charAt(s.length - 1);
    s.substring(1, 4);
    s.slice(1, 4);
    s.slice(-4);
    s.indexOf("l");
    s.lastIndexOf("l");
    s.indexOf("l", 3);
    s.split(",");
    s.replace("h", "H");
    s.toUpperCase();
    s[0];
    s[s.length - 1]; debugger;


    function name(o) {
        if (o == undefined) debugger; {
            
        }

    }

    var r = new RegExp("js");
    g = JSON.stringify(s);
    pageXOffset = JSON.parse();
    toJSON();
</script>