Using dynamic fields in javascript calculations

Quite often the problem occurs that one might need a data from entries field in the calculation of other field values. This is the case when you need a property or a value from a linked form which is connected to the current form via a data from entries field.

In JavaScript my solution works as follows:

The data from entries field is displayed as a drop down menu and has the field id number 99 . This type of field has two "values" - the entry id number of the entry it is displaying data from and - the actually displayed text.

1. getting the different values:

var linkedEntryID ;

var displayedText ;

linkedEntryID = $('select[name="item_meta[99]"]').find(':selected').val() ;

displayedText = $('select[name="item_meta[99]"]').find(':selected').text();

For a field calculation the script should be executed when any of the variables (for instance var1, var2, var3) that determine the calculated field change. This is why the entire script is embedded in the $('var1,var2,var3').change(function(){/*script goes here*/}) which is embedded into jQuery(document).ready(function($){/*change function goes here*/}) ; function.

2. To execute the script when the data from entries selection changes the entire construction look like:

jQuery(document).ready(function($){

$('select[name="item_meta[99]"], var2, var3').change(function(){

/*script goes here*/

}) ;

}) ;

Attention has to be paid to the correct use of the ' and '' signs in JavaScript. I think they are not completely interchangeable. They act like different types of brackets. Before using the other one the first type must have been closed.

So, you could write as well:

jQuery(document).ready(function($){

$("select[name='item_meta[99]'], var2, var3").change(function(){

/*script goes here*/

}) ;

}) ;

but not:

jQuery(document).ready(function($){

$('select[name='item_meta[99]'], var2, var3').change(function(){

/*script goes here*/

}) ;

}) ;

With the linkedEntryID the information is available to get data from the linked entry. I just don't know how to do this via javascript - it is probably not implemented since it requires interaction with the server.

In a PhP script I use FrmProEntriesController::get_field_value_shortcode(array('field_id' => 12, 'entry_id' => linkedEntryID));

An interesting observation is that I could only use one of the two commands successfully:

linkedEntryID = $(‘select[name="item_meta[99]“]’).find(‘:selected’).val() ;

displayedText = $(‘select[name="item_meta[99]“]’).find(‘:selected’).text();

I could either get the text value of the field or the linkedEntryID not both in a script.

I finally solved the problem to access data from the linked form by adding a second data from entry field that would show the requested information when the first data from entry field was set to anything (conditional display - this links the second field to the entry accessed in the first data from entries field). The second data from entries field showing the desired information is mounted after a section heading that will never show in the form (unfulfillable or extremely unlikely conditional display). Even though the field does not show up in the form its data can be accessed with conventional javascript access code - in my case:

desiredLinkedDataValue = $("#field_field_key_here").val() ;

because I configured the second data from entry field to just show the value. With this configuration I can do calculation based on information stored in another form which is selected by the user via its form name or any other information meaningful to the user but not directly relevant for the calculation and the script does the calculation every time the user changes the selection in the first data from entries field.