A Client Script lets you dynamically define a custom Form Script that is executed on a user's browser. If you choose to utilize non standard tools or libraries, make sure to test them on different browsers to ensure compatibility across your userbase.

In Version 13, Custom Script was renamed to Client Script

1. How to create a Client Script

To create a Client Script

  1. To add/edit Client Script, ensure your role is System Manager.
  2. Type "New Client Script" in the awesomebar and hit enter to create a new Client Script document.
  3. Select the DocType whose form you wish to customize.
  4. Update the script using the preset template and save.
  5. Head over to the DocType you've customized and see the changes.

2. Features

As compared to the restrictive nature of Server Scripts, everything is fair game in Client Scripts. This is because the frontend APIs are secure by design. You can utilize all of JavaScript APIs, along with Frappe's and any other JS or CSS library you might've customized Desk with.

The validations you add through Client Script will only be applied while using the standard form view accessible through the browser. In case you wish for those to be applied through API or System Console access too, use Server Scripts.

3. Examples

3.1 Custom validation

Add additional form validations while creating or updating a document from Frappe's standard form view.

// additional validation on Task dates
frappe.ui.form.on('Task', 'validate', function(frm) {
    if (frm.doc.from_date < get_today()) {
        msgprint('You can not select past date in From Date');

3.2 Fetching values on field updates

Fetch local_tax_no on changing value of the customer field.

cur_frm.add_fetch('customer', 'local_tax_no', 'local_tax_no');

3.3 Customize field properties

Make a field ibsn read only after creating the document.

// make a field read-only after saving
frappe.ui.form.on('Task',  {
    refresh: function(frm) {
        frm.set_df_property('ibsn', 'read_only', !frm.is_new());

3.4 Customize field properties

Calculate incentives on a Sales Invoice form on save.

// calculate sales incentive
frappe.ui.form.on('Sales Invoice',  {
    validate: function(frm) {
        // calculate incentives for each person on the deal
        total_incentive = 0
        $.each(frm.doc.sales_team,  function(i,  d) {
            // calculate incentive
            let incentive_percent = 2;
            if(frm.doc.base_grand_total > 400) incentive_percent = 4;
            // actual incentive
            d.incentives = flt(frm.doc.base_grand_total) * incentive_percent / 100;
            total_incentive += flt(d.incentives)
        frm.doc.total_incentive = total_incentive;