OnChange - Pass 5 Values To The CalcAvg() Function?

In our class we were assigned a project to create a Web page with 5 text boxes, each with a value attribute of zero. When the user changes the values, it is supposed to call a caclAvg() function. How do I pass 5 values to the calcAvg() function? It specifically states in our book to create an onChange event handler for each textbox. Wouldn't it be easier to somehow create a variable onChange, then after all 5 textboxes have changed, pass the 5 variables along to the function? I know the following code is a mess, I've tried so many ways now. I'm sure this is an easy, routine procedure for most of you.

function calcAvg(value1) {
var functionValue = value1;
}
<form action="" method="post" name"values">
<input type="text" name="value1" value="0" onchange="calcAvg(this.value)" />
<input type="text" name="value2" value="0" onchange="calcAvg(this.value);" />
[Code]....