How do I get this javascript to run every second?

You can use setTimeout to run the function/command once or setInterval to run the function/command at specified intervals.

var a = setTimeout("alert('run just one time')",500);
var b = setInterval("alert('run each 3 seconds')",3000);

//To abort the interval you can use this:
clearInterval(b);

Use setInterval() to run a piece of code every x milliseconds.

You can wrap the code you want to run every second in a function called runFunction.

So it would be:

var t=setInterval(runFunction,1000);

And to stop it, you can run:

clearInterval(t);

Use setInterval:

$(function(){
setInterval(oneSecondFunction, 1000);
});

function oneSecondFunction() {
// stuff you want to do every second
}

Here's an article on the difference between setTimeout and setInterval. Both will provide the functionality you need, they just require different implementations.