var validationHandlers = new Array();
function register_validation_handler ( validation_handler ) {
    // Add `function` to the list of functions that will be called whe
+n validating
    // the page.
    validationHandlers.push( validation_handler );
    return validation_handler;
}
function validate_form () {
    /* Global function for validating a form. This examines the valida
+tionHandlers
     * array and produces an aggregate result. If there were failures 
+then the user
     * is prompted and the function returns false else it returns true
+.
     *
     * This function is the only intended interface to the validation 
+functions here
     * beyond the register_validation_handler( ... ) function.
     */
    // Get an object to hold everything for us.
    var overall = new ValidationResult();
    // Loop through each installed validation handler and add the indi
+vidual result to the
    // cumulative total.
    for (var ix = 0; ix < validationHandlers.length; ix++) {
        // Retrieve each handler in turn.
        var handler = validationHandlers[ ix ];
        // And execute it.
        var result = handler();
        // Maintain an overall failure state
        if (result.failed)
            overall.failed = result.failed;
        // Copy over the focus field if it hasn't been set before
        if (overall.focus_field == null && result.focus_field != null)
            overall.focus_field = result.focus_field;
        // Pass in the bad field failure messages.
        overall.bad_fields = overall.bad_fields.concat( result.bad_fie
+lds );
        // And any other errors.
        overall.errors = overall.errors.concat( result.errors );
    }
    // Validation is now complete.
    // Generate a 'bad fields' message if there are any.
    if (overall.bad_fields[0] != null) {
        if (overall.bad_fields.length > 1)
            overall.error("Please check the following fields for accur
+acy:\n"+
                overall.bad_fields.join("\n") );
        else
            overall.error("Please check the " + overall.bad_fields[0] 
++ " field for accuracy.");
    }
    // Report any and all error messages
    if (overall.errors[0] != null)
        alert(overall.errors.join("\n\n"));
    // Since success is the opposite of failure... negate failure to r
+eturn the success value.
    return ! overall.failed
}
function ValidationResult () { 
    /*
     * The ValidationResult constructor.
     * For normal validation see the function validate_form().
     *
     * Execute ` ... = new ValidationResult(); ` to create a new objec
+t.
     *
     * By default, validation objects are considered to have passed mu
+ster. Your validation
     * code is expected to signal a failure by logging an error messag
+e with error(...) or bad data
     * with bad_field( ... ).
     *
     * The end result can be examined by looking at the failed propert
+y.
     */
    // Create a new generic object
    var result = new Object;
    // Set all of the properties to their default values.
    result.failed = false;
    result.bad_fields = new Array();
    result.errors = new Array();
    result.exit_immediately = false;
    result.focus_field = null;
    // Install methods into the new object.
    result.bad_field = validation_bad_field_method;
    result.error = validation_error_method;
    result.debug = validation_debug_method;
    result.debug = validation_debug_method;
    return result;
}
function validation_bad_field_method ( field_name, message ) {
    // Mark this field as a failure with a message
    if ( this.focus_field == null)
        this.focus_field = field_name;
    // Do some auto-defaulting.
    if ( message == null || message == '' )
        message = field_name;
    this.bad_fields.push( message );
    this.failed = true;
    return this;
}
function validation_error_method ( message ) {
    // Add 'message' to the list of errors, mark the object as failing
+ validation
    this.errors.push( message );
    this.failed = true;
    return this;
};
function validation_debug_method () {
    // Prompt the user with the internal state of the validation objec
+t.
    alert(
        'failed:'+this.failed+
        "\nbad_fields:"+this.bad_fields.join(",")+
        "\nerrors:"+this.errors.join(",")+
        "\nexit_immediately:"+this.exit_immediately+
        "\nfocus_field:"+this.focus_field);
    return this;
}
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