Comparing input fields using JQuery

I currently have an input form. There are two entries for each input class as follows:

<form>
    <input type="text" name="firstname_a" class="firstname" disabled="disabled" />
    <input type="text" name="firstname_b" class="firstname" />
    <input type="text" name="surname_a" class="surname" disabled="disabled" />
    <input type="text" name="surname_b" class="surname" />
    <input type="submit" value="submit" />
</form>

On submission I want JQuery to check whether or not value a matches value b (value a has been entered by the end user, value b has been entered by a outworker working for a vetting company). The form could have upto 470 input fields, these are stored in a database dependant upon the type of vetting being carried out. I don't, therefore, want to have to type out 470 times!:

if($('input["name=firstname_a"]').val() == $('input["name=firstname_a"]').val())
{
  // do something
}
else
{
  // do something else
}

Rather I would like to find a dynamic way to do this, possibly using the serializeArray() function, but I'm s开发者_开发百科truggling! All or any help would be greatly appreciated.

---

You can cycle through .each input ending in _a and do the comparison with its _b counterpart:

$('#target').submit( function() {

    // Iterate over each input with name ending in _a
    $('input[name$="_a"]').each( function() {

        // Get the base name by removing _a
        var name = $(this).attr('name').replace(/_a$/, '');

        // Compare _a to _b
        if( $('input[name="'+name+'_a"]').val() != $('input[name="'+name+'_b"]').val()) {
             alert(name+" field does not match!");   
        }
    });

    return false;
});

Example:

http://jsfiddle.net/jtbowden/yqMGG/

Here is a version where all mismatches are saved and alerted at the end:

http://jsfiddle.net/jtbowden/amsJj/

Or a version that highlights the errors:

http://jsfiddle.net/jtbowden/V8xJX/

---

I'd use an each over the collection matching names that end in _a, then find the corresponding _b and check their values. Set a variable in the outer scope to track whether any invalid inputs have been found.

var valid = true;
$('input[name$="_a"]').each( function() {
    var $a = $(this);
    var bName = $a.attr('name').replace(/_a/,'_b');
    var $b = $('input#' + bName);
    if ($a.val() != $b.val()) {
        // add a validation message for b?
        valid = false;
        // return false; // only if you want to stop after the first one
    }
});

return valid;

---

You can use the ends with selector $= and iterate over the lists assuming they're both in the same order and there's always a _b value for an _a value:

var aSet = $('input[name$="_a"]'),
    bSet = $('input[name$="_b"]'),
    al = aSet.length;

for (var i = 0; i < al; i++) {
  if (aSet.eq(i).val() == bSet.eq(i).val()) {
    // do something
  } else {
    // do something else
  }
}

---

are you trying to evaluate all the elements at the same time? if so, this belongs on the server side after the form submit. if you are rying to do this after each field blur then

<input type="hidden" name="firstname_a" class="firstname"  />
<input type="text" name="firstname_b" class="firstname eval" rel="#firstname_b"/>
$('.eval').live('blur',function(){
   if($(this).val()==$($(this).attr('rel')).val()){
    ...
  }else{
    ...
  }
});

and if you REALLY want to do it at submit time then

$('.eval').each(function(){
       if($(this).val()==$($(this).attr('rel')).val()){
        ...
      }else{
        ...
      }
    });