If Statement Help, Urgently Need Help!!!!!

I'm developing a JavaScript program that uses an if statement to determine the tax payable income with a sliding tax scale for example:
the client enters their weekly Income.

function AnnualSalary() {
A = document.form1.txtws.value
B =(parseInt(A ) * 52)

if ( B<= 6000) {alert(" Annual tax 0") }

else if(6001<=B<=80000 {alert("")}

My Problem is in this next part I want to be able to say c=0.30*b in the else if statement and then display the result in an alert.

Am i able to do this, or is there a better way of going about this then what am doing?

I'm very new to javascript so its all still very confusing to me.

 

You're doing fine -
} else {
c=0.30*b;
alert (c);
}