I have many functions like this, and I don't know should I make j and k a local variable or will there be any abnormal problems?

```
var j=10,k=20;
var i=j+k*2;
console.log('helloworld'+i);
function plus(j,k){
 var i=j+k;
 console.log('plus '+i);
 //...etc
}

function formular(j,k){
 var i=j*k+123;
 console.log('formular '+i);
 //...etc
}
plus(-10,-20);
setInerval(function(){formular(22,33)},1000);
setInerval(function(){plus(-102,-33)},1000);

```

Or should I write like

```
function(var j, var k){ }

```

??