Some gravity form field manipulations: character counter (requires plugin), field validations, preset form values, post set form value.

gistfile1.txt

<?php 
add_action('wp_footer', 'add_char_counter');
function add_char_counter() {
    if ( is_page( array( 'add-a-highlight', 'add-a-publication' ) ) ) { ?> 
        <script src="/wp-content/themes/ameriflux/library/js/textcounter.min.js"></script>
        <script type="text/javascript">
            jQuery('.amx-title input').textcounter({
            max: 250,
            countDownText: "Characters Left: "
            });
            jQuery('.amx-descrip textarea').textcounter({
                max: 1000,
                countDownText: "Characters Left: "
            });
        </script> 
    <?php }  
}

add_action('wp_footer', 'makeyear');
function makeyear() {
    if ( is_page( array( 'send', 'add-a-highlight', 'add-a-publication' ) ) ) { ?> 
        <script type="text/javascript">
        	jQuery('.amx-pubdate input').on('change', function() {
        		var xdate=jQuery('.amx-pubdate input').val().substr(0,4);
                jQuery('.amx-pubyear input').val(xdate);
            	});
        </script> 
    <?php }  
}

add_filter("gform_field_validation_4_10", "pageno_validation", 10, 4);
function pageno_validation($result, $value, $form, $field){
    $parts=explode("-",$value);
    if (count($parts) != 2) $result["is_valid"] = false; 
    
    if( ! $result["is_valid"] ){
        $result["message"] = "Please enter start and end pages eg: 985-1000";
    }
    return $result;
}

add_filter("gform_field_validation_4_11", "pubdate_validation", 10, 4);
function pubdate_validation($result, $value, $form, $field){
    $parts=explode("/",$value);
    $count=count($parts);
    if ($parts[0]<1900 && $parts[0]>2020) $result["is_valid"] = false; 
    else if ($count>1 && $parts[1]>13) $result["is_valid"] = false; 
    else if ($count>2 && $parts[2]>31) $result["is_valid"] = false; 

    if( ! $result["is_valid"] ){
        $result["message"] = "Please enter a valid date YYYY or YYYY/MM or YYYY/MM/DD";
    }
    return $result;
}

//add_filter("gform_save_field_value", "save_field_value", 10, 4);
function save_field_value($value, $lead, $field, $form){
        if(absint($form["id"]) <> 5)
                return $value;
        if ($field["id"]==3)
                return 2001;
        else
                return $value;
}

//add_filter("gform_field_value_fonty", "set_field_value", 10, 4);
function set_field_value(){
	     /* prepopulate a field with advanced tab dynamic load parameter=fonty */
         return 2005;
}

/*
function custom_validation($validation_result){
?>
    <script type='text/javascript'>
        console.log("Working");
    </script>
<?php
    return $validation_result;
}
add_filter('gform_validation', 'custom_validation');
*/