I have a form with multiple checkboxes and I want to use JavaScript to make sure at least one is checked. This is what I have right now but no matter what is chosen an alert pops up.

JS (wrong)

function valthis(){

 if (document.FC.c1.checked) {

   alert (thank you for checking a checkbox)

  } else  {

   alert (please check a checkbox)

  }

}

HTML

<p>Please select at least one Checkbox</p>

<br>

<br>

<form name = FC>

<input type = checkbox name = c1 value = c1/> C1 

<br>

<input type = checkbox name = c1 value = c2/> C2

<br>

<input type = checkbox name = c1 value = c3/> C3

<br> 

<input type = checkbox name = c1 value = c4/> C4 

<br>

</form>

<br>

<br>



<input type = button value = Edit and Report onClick = valthisform();>

So what I ended up doing in JS was this:

function valthisform(){

 var chkd = document.FC.c1.checked || document.FC.c2.checked||document.FC.c3.checked|| document.FC.c4.checked



 if (chkd == true){



 } else {

    alert (please check a checkbox)

 }



}

I decided to drop the Thank you part to fit in with the rest of the assignment. Thank you so much, every ones advice really helped out.