prevent Duplicate values using Jquery Validation

Question

I have form and form text field which generates dynamically using JSP. And I\'m using Jquery validation but want to add functionlaty to prevent duplicate entry in the form.<

Answer 1

I know this is an old question and the answer is slightly off track from the original question but I was pulling my hair out for a while as I only wanted to check a specific field VS another specific field and could't get it to work any other way. The jQuery validation comes with an equalTo validator. https://jqueryvalidation.org/equalTo-method/

Which in the source code looks like:

equalTo: function( value, element, param ) {

        // Bind to the blur event of the target in order to revalidate whenever the target field is updated
        var target = $( param );
        if ( this.settings.onfocusout && target.not( ".validate-equalTo-blur" ).length ) {
            target.addClass( "validate-equalTo-blur" ).on( "blur.validate-equalTo", function() {
                $( element ).valid();
            } );
        }
        return value === target.val();
    }

take this code and use the addMethod function like so swapping the === to !==:

jQuery.validator.addMethod("notEqualTo", function(value, element, param) {
        // Bind to the blur event of the target in order to revalidate whenever the target field is updated
        var target = $( param );
        if ( this.settings.onfocusout && target.not( ".validate-equalTo-blur" ).length ) {
            target.addClass( "validate-equalTo-blur" ).on( "blur.validate-equalTo", function() {
                $( element ).valid();
            } );
        }
        return value !== target.val();
        // condition returns true or false
    }, "Values must be unique");

Then apply in rules section:

 'first_name':{
      required: true,
      notEqualTo: '#last_name'
  }