Form Client Scripting

Scripting Forms

Now we have created a basic system that works out of the box without us having to write any code. Let us now write some scripts to make the application richer and add validations so that the user does not enter wrong data.

Client Side Scripting

In the Library Transaction DocType, we have only one field for Member Name. We have not made two fields. Now this could well be two fields (and probably should), but for the sake of example, let us consider that we have to implement this. To do this we would have to write an event handler for the event when the user selects the library_member field and then access the member resource from the server using REST API and set the values in the form.

To start the script, in the library_management/doctype/library_transaction folder, create a new file library_transaction.js. This file will be automatically executed when the first Library Transaction is opened by the user. So in this file, we can bind events and write other functions.


frappe.ui.form.on("Library Transaction", {
    "library_member" : function(frm) {{
            "method": "frappe.client.get",
            args: {
                doctype: "Library Member",
                name: frm.doc.library_member
            callback: function (data) {
                    frm.docname, "member_name",
                    + (data.message.last_name ?
                        (" " + data.message.last_name) : ""))
  1. frappe.ui.form.on(doctype, fieldname, handler) is used to bind a handler to the event when the property library_member is set.
  2. In the handler, we trigger an AJAX call to frappe.client.get. In response we get the requested object as JSON. Learn more about the API.
  3. Using frappe.model.set_value(doctype, name, fieldname, value) we set the value in the form.

Note: To check if your script works, remember to 'reload' the page before testing your script. Client script changes are not automatically picked up when you are in developer mode.

Next: Controllers