Using function in Javascript

Question

Example:

function pcs()
{
    var t1 = document.getElementById("tot1").value
    var pb = document.getElementById("pcbox").value
    var pc = ""

    if (t1==! && pb==!)
    {
     document.getElementId("rbox").innerHTML = ""
    }
}

My question is if t1 and pb are null the function pcs() is not called... Why?

Answer 1

if(t1==! && pb==!) --> this is absolutly wrong.... What are you trying to check?

Maybe if(t1!="" && pb!="")?

Answer 2

The line if(t1==! && pb==!) is nonsense - did you mean if (!t1 && !pb)?

Answer 3

You've posted no code to show the function pcs() being called. Post more code.