newbie help? please

sorry if i sound dumb, but these two functions work ok on their own but as soon as i put them together they dont. Not too clued up on passing variables.

Also the second part of the function is to ensure that one of 4 radio's are checked, but only if a checkbox is checked, however, the alert pops up even if the checkbox isnt checked?!

Any help much obliged!


function valid(contactform) {
var field = contactform.tel;
var telno = parseInt(field.value);
var selection = -1;
if (!telno) {
alert("Please enter a valid number");
field.focus();
field.select();
return false}
else {
alert("ok");
return true;
}


for(i=0;i<contactform.choice.length;i++){
if(contactform.choice[i].checked){
selection =i
alert("Thankyou, a brochure for " +contactForm.choice[i].value+ " is on its way")
}
}
if(selection == -1){
alert("please select a brochure")
return false
}


return true
}