Disable button by clearing checkbox

[tsubasa]

I have a form where a user can select items via a check box. Once an item is checked it will enable a button to appear so that the user can add the items to a shopping cart. I have the first part of the JavaScript working which allows the button to appear if the checkbox is true.

The problem that I am having is when I decide to deselect the last remaining box. It does not disable the add button. The first part works, the second part does nothing. Also, there are no JavaScript errors.

-Tsu

function boxChecked(field)
{
  var 1 = 0;
  if(field[i].checked = true)
  {
   var x=document.getElementById("mybutton")
   x.disable=false;
  }
  else
  if(field[i].checked = false)
  {
  var x=document.getElementById("mybutton")
  x.disable=true;

[Dormilich]

that’s because = is the assignment operator.

tip: reverse variable and value.

if (box.checked = false) // no error

if (false = box.checked) // error: cannot assign to a constant

[tsubasa]

Hello Dormilich,

Although this does not produce an error, it does not work. The same remains even with your recommendation. The first part works, but the 2nd part does nothing. Thanks for replying anyhow.

-Tsu

[Dormilich]

er, my code was not meant as a working demonstration. it is an example to demonstrate the problem.

you are just mistaking the assignment operator for the comparison operator. the given code shows a possibility to write code in a way that you can’t mistake one for the other.

[tsubasa]

Understood,

Thanks!