Custom validator for existing value does not work

Question

I'm using jQuery Form validator, I created a custom validator to check if the input value already exists, but It's not working.

var seen = {};
$.formUtils.addValidator({
    name: 'value_exists',
    validatorFunction: function(value, $el, config, language, $form) {

        if (seen[value]) {
            return false;
        } else {
            seen[value] = true;
            return true;
        }
    },
    errorMessage: 'This value exits already',
    errorMessageKey: ''
});

Edit : For example I type in the first input the value TEST, and then in the second I type TEST again, whice normally shows the error. when I try to replace that value with another one (MASTER in this example) the error does not go away.

Here is what console.log(seen) shows :

Object {TEST: true, M: true, MAS: true, MAST: true, MASTER: true}

Answer 1

Solved the problem with a better algorithm :

$.formUtils.addValidator({
    name: 'duplicated',
    validatorFunction : function (value,$el,config,language,$form){
        var ret = true;
        $form.find('[name="' + $el.attr('name') + '"]').each(function(index, elm) {
            if($el[0].id !== elm.id && elm.value === value) ret = false;
        });
        return ret;
    },
    errorMessage : 'The value exists already.',
    errorMessageKey : ''

});

What I do here is : for all inputs with X name, for each input, if the id's are different(to prevent the element to compare itself), and the value is the same, throw an error (duplicate).