Question

I must have read about arguments in functions and how they are variables and/or objects and pass value a million times and still real life examples keep throwing me off. The keyword “this” in this example points to the object of the function, being the form element. OK got that.

Now the function outside the window.onload event handler has a parameter named “frm”. My question is whether it’s necessary to give this parameter the same name as the id of the form element that will be passed to it (in this case ‘frm’)? I thought this didn’t matter. For all it mattered one could put anything inside the argument just as long as it’s reused as a local variable inside of the function itself.

window.onload = function() {
    // validation for submit button
    document.frmFlight.onsubmit = function() {
        //console.log("what is 'this'?: "+this);
        return validate(this);
    }       
}

//----------------------------------------------------------
function validate(frm) {
    var valid = true;
    return valid;
}   

Answer 1

It’s not clear exactly what you’re asking, but the name you give the argument in the function signature doesn’t relate in any way to the name of anything you might be passing into the function. It can be (just about) anything you want it to be. These are all equivalent:

function validate(frm) {
    // ...
}

function validate(theForm) {
    // ...
}

function validate(foo) {
    // ...
}

Your use above is just fine, because when you set up an event handler in the way you have (by assigning a function to the onsubmit property), when the event fires, the function will be called such that this references the DOM element for the form. Assuming that’s what the validate function uses its argument for (regardless of what it calls it), you’re in good shape.