check a checkbox

[bewise]

When a checkbox is checked, I would like a group of checkboxes on a page to be automatically checked.

I was thinking of going about it like this:

- value of top checkbox = check1
- values of all checkboxes that should be automatically checked (when top checkbox is checked)= check1_1, check1_2, check1_3 etc
- on the onclick event of the top checkbox, a piece of javascript would be executed that would iterate through all the checkboxes.

x = 1;
while (x < 10)
{
check1_(value of x).checked = true;
x++;
}

How could i go about doing the above in javascript?

Sorry for this, its jusst I dont know anythin about javascipt.

Many thanks

[gregor002]

on the onclick event of the top checkbox, a piece of javascript would be executed that would iterate through all the checkboxes.

Yes, that sounds right. Try something like:

window.onload = function() {
  var cbx = document.getElementById("check1");
  cbx.onclick = function() {
    if (cbx.checked) { 
      applyCheck(true);
    } else {
      applyCheck(false);
    }
  }
}

function applyCheck(bool) {
  var inputs= document.getElementsByTagName("INPUT");
  for (var x=0; x<inputs.length; x++) {
    if (inputs[x].type == "checkbox") {
        bool == true ? inputs[x].checked = true : inputs[x].checked = false;
    }
  }
}

So... when the page loads, get the checkbox with id "check1". If check1 is checked, check other boxes on the page otherwise uncheck. HTH....