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jQuery Validation using the class instead of the name value

Answer 1

A:

Here's my solution (requires no jQuery... just JavaScript):

function argsToArray(args) {
  var r = []; for (var i = 0; i < args.length; i++)
    r.push(args[i]);
  return r;
}
function bind() {
  var initArgs = argsToArray(arguments);
  var fx =        initArgs.shift();
  var tObj =      initArgs.shift();
  var args =      initArgs;
  return function() {
    return fx.apply(tObj, args.concat(argsToArray(arguments)));
  };
}
var salutation = argsToArray(document.getElementsByClassName('salutation'));
salutation.forEach(function(checkbox) {
  checkbox.addEventListener('change', bind(function(checkbox, salutation) {
    var numChecked = salutation.filter(function(checkbox) { return checkbox.checked; }).length;
    if (numChecked >= 4)
      checkbox.checked = false;
  }, null, checkbox, salutation), false);
});

Put this in a script block at the end of <body> and the snippet will do its magic, limiting the number of checkboxes checked in maximum to three (or whatever number you specify).

Here, I'll even give you a test page (paste it into a file and try it):

<!DOCTYPE html><html><body>
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<input type="checkbox" class="salutation">
<script>
    function argsToArray(args) {
      var r = []; for (var i = 0; i < args.length; i++)
        r.push(args[i]);
      return r;
    }
    function bind() {
      var initArgs = argsToArray(arguments);
      var fx =        initArgs.shift();
      var tObj =      initArgs.shift();
      var args =      initArgs;
      return function() {
        return fx.apply(tObj, args.concat(argsToArray(arguments)));
      };
    }
    var salutation = argsToArray(document.getElementsByClassName('salutation'));
    salutation.forEach(function(checkbox) {
      checkbox.addEventListener('change', bind(function(checkbox, salutation) {
        var numChecked = salutation.filter(function(checkbox) { return checkbox.checked; }).length;
        if (numChecked >= 3)
          checkbox.checked = false;
      }, null, checkbox, salutation), false);
    });
</script></body></html>

Delan Azabani 2010-05-06 10:30:23

Hi, that's brilliant - thanks for your response Delan, however, the rest of the form (which I haven't shown) uses jQuery as well - so I'd prefer it if I can use jQuery in this example, because it all needs to be validated at the same time.

Matt 2010-05-06 10:42:41

Answer 2

+1 A:

You can add the rules based on that selector using .rules("add", options), just remove any rules you want class based out of your validate options, and after calling $(".formToValidate").validate({... });, do this:

$(".checkBox").rules("add", { 
  required:true,  
  minlength:3
});

Nick Craver 2010-05-06 11:07:29

Thanks Nick, much appreciated :o)

Matt 2010-05-06 19:02:11

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jQuery Validation using the class instead of the name value

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