js代码错误

Question

Can someone tell me why this JS code do not work?

It should print time every second:

function stampajDatum(){
    var now = new Date();
    var sat = now.getHours();
    var mins = now.getMinutes();
    var sec = now.getSeconds();
    document.write(sat + ":" + mins + ":" + sec);
}
setInterval("stampajDatum()", 1000);

Answer 1

The first message I'm getting in my console is about that implied eval. Take away the quotes around the function name in setInterval("stampajDatum()", 1000); (Making it setInterval(stampajDatum(), 1000); )

I don't usually use setInterval() , but I know that setTimeout() works. Here's an example:

function stampajDatum(){
    var now = new Date();
    var sat = now.getHours();
    var mins = now.getMinutes();
    var sec = now.getSeconds();
    document.write(sat + ":" + mins + ":" + sec);
    setTimeout(stampajDatum(), 1000);
}
stampajDatum();

Answer 2

function stampajDatum(){
    var now = new Date();
    var sat = now.getHours();
    var mins = now.getMinutes();
    var sec = now.getSeconds();
    document.write(sat + ":" + mins + ":" + sec);// the problem is here
    //This writes content to a place after script block
    //if the script is in head then nothing is visible.
    //use something like this:
    //document.getElementById('timer').innerHTML = sat + ":" + mins + ":" + sec;
}
setInterval("stampajDatum()", 1000);//This is OK but setInterval(stampajDatum, 1000); is better. 
//Note that there is no () after stampajDatum