Using JQuery Validate Plugin to validate multiple form fields with identical names

Instead of changing the source file jquery.validation you can simply override the function you need to edit only in the pages that requires it.

An example would be:

$.validator.prototype.checkForm = function() {
    //overriden in a specific page
    this.prepareForm();
    for (var i = 0, elements = (this.currentElements = this.elements()); elements[i]; i++) {
        if (this.findByName(elements[i].name).length !== undefined && this.findByName(elements[i].name).length > 1) {
            for (var cnt = 0; cnt < this.findByName(elements[i].name).length; cnt++) {
                this.check(this.findByName(elements[i].name)[cnt]);
            }
        } else {
            this.check(elements[i]);
        }
    }
    return this.valid();
};

This might not be the best solution, but at least it avoids editing source files, that could be replaced later, when a new version releases. Where your overridden function might or might not break.

Old thread I know but I came across it in search of the fix to the same problem.

A more elegant solution has been posted here: http://web-funda.blogspot.com/2009/05/jquery-validation-for-array-of-input.html

You simply edit jquery.validate.js and change the checkForm to

    checkForm: function() {
    this.prepareForm();
    for ( var i = 0, elements = (this.currentElements = this.elements()); elements[i]; i++ ) {
        if (this.findByName( elements[i].name ).length != undefined && this.findByName( elements[i].name ).length > 1) {
            for (var cnt = 0; cnt < this.findByName( elements[i].name ).length; cnt++) {
                    this.check( this.findByName( elements[i].name )[cnt] );
            }
        } else {
            this.check( elements[i] );
        }
    }
    return this.valid();
}