Question

I found the solution to reset radiobuttons.

This next example works well for 4 radiogroups:

<script type="text/javascript">
function uncheckRadio()
{   
    for(x=0; x<document.QuizForm.Q01.length; x++){document.QuizForm.Q01[x].checked = false;}
    for(x=0; x<document.QuizForm.Q02.length; x++){document.QuizForm.Q02[x].checked = false;}
    for(x=0; x<document.QuizForm.Q03.length; x++){document.QuizForm.Q03[x].checked = false;}
    for(x=0; x<document.QuizForm.Q04.length; x++){document.QuizForm.Q04[x].checked = false;}
}   

</script>

But now I want to reset 80 radiogroups in one single (multiple choice) form by applying a nested loop to iterate from 01 to 80.

Tried several ways to use nested loops, but somehow I cannot find a way to get the Q01, Q02 etc. iteration to work…

Many thanks

Answer 1

In the browser that supports the standards, you could use querySelectorAll, if you’re sure that there are no other radio with name attributes that starts with “Q”:

var radios = document.QuizForm.querySelectorAll("input[type=radio][name^=Q]:checked");

for (var l = radios.length; l > 0;)
  radios[--l].checked = false;

Otherwise you can use the square bracket notation:

var elements = document.QuizForm.elements;
var prefix;

for (var l = 80; l > 1; l--) {
  prefix = l < 10 ? "Q0" : "Q";
  elements[prefix + l].checked = false;
}