How can I validate a dropdown box to NOT accept the default value?

Question

I have a fillable form where I need the user to select their "Number of Employees". I have added several ranges as their options in a dropdown box (1-10, 11-25, 26-50, 50+). My issue is the "defult value" is set to "1-10" and people submit it without changing it to the correct value.
I have changed the default value to "--Select One--", but it still lets them submit the form with that value entered.
I am assuming I need some sort of validation script that will basically say - "If the value in this field is --Select One-- do not submit the form, but give an error that says 'please select your number of employees" or something along those lines.
Basically I just want them to pick something as opposed to just submiting it with the default value.
I have looked all over and am not very good with JS.

Answer 1

You can not have the default value set to a real possible value. You need a value that should be selected.
Then for your submit script you need to test all of your required fields to make sure they are not at the default value.
You make a variable that assumes all the required fields are completed and then check each field and if any one still has the default value you set your variable to "false" and then when you have checked all the fields you test your variable's value and only if it is true to you submit the form.
var bSumbit = ture; // logical variable for submission test
// test drop down # of employess
this.getField("Number of Employees".).required = false; // clear required property
if(this.getField("Number of Employees".).value == "--Select One--") {
bSubmit = false;
this.getField("Number of Employees".).required = true; // set required property
if(bSubmit) {
// your submit acation;
} else {
app.alert("Not all required fields properly completed", 0, 1);