how do i assign an onchange function to a select field within my javascript code?

i want to dynamically assign an onchange function to a select field in my javascript code.

so lets say i have this code:

function eventHandler(param1) {

           doSomeStuff(param1);
}

selectField.onchange=eventHandler("blah");



obviously this is the wrong way, what is the correct way?

selectField.onchange = function() { eventHandler("blah"); }


is this the correct way?