function quiz_grade() {

if (document.getElementById && document.createTextNode) { 

var q_answers = new Array()
q_answers[0] = "a"; // Answer for Question 1
q_answers[1] = "c"; // Answer for Question 2
q_answers[2] = "b"; // Answer for Question 3
q_answers[3] = "d"; // Answer for Question 4
q_answers[4] = "b"; // Answer for Question 5

var num_right = 0;
var num_wrong = 0;
var the_score = 0;

for (c=0; c<q_answers.length; c++) {
var q_n = "qu_" + (c+1);
var q_a = document.getElementById(q_n).value; 
var q_a_exp = "^"+q_answers[c]+"$";
var q_a_tomatch = new RegExp(q_a_exp, "i");
var q_a_ismatch = q_a_tomatch.test(q_a); 
if (q_a_ismatch) {
num_right++; 
}
else {
num_wrong++;
}
}

the_score = Math.round(num_right/q_answers.length*100); 
window.alert("You got "+num_right+"/"+q_answers.length+" correct for a score of "+the_score+"%."); 
return false; 

}

}