How to make attachment mandatory based on condition for record producer in service portal?

[Srinivas Goud K]

I need to make attachment is mandatory based on condition. There is a check box in the form If I select that one then it should become attachment mandatory how to implement that please help me out.

I have used below Script but it is become mandatory for entire form I want it for particular variable only

Please check attachment 

function onSubmit() {

    var cat_id = g_form.getValue('sysparm_item_guid');
    var gr = new GlideRecord("sys_attachment");
    gr.addQuery("table_name", "sc_cart_item");
    gr.addQuery("table_sys_id", cat_id);
    gr.query();
    if (!gr.next()) {
        alert("Attachment is mandatory if you select Preapproved");
        return false;
    }
}

[Ghulam Gose Ala]

Write an on submit Catalog Client script and put the backend value of your checkbox variable in place of "YOUR_Check_box".

function onSubmit() {
    //Type appropriate comment here, and begin script below  
    var catalogItemID = g_form.getValue('sysparm_item_guid');
    var test = g_form.getValue('YOUR_Check_box');

    if (test == 'true') {

        var count = getSCAttachmentCount();
        if (count <= 0) {
            getMessage('mandatory_attachment', function(msg) {
                g_form.addErrorMessage(msg);
            });
            return false;

        }
    } else {

        return true;
    }
}

Mark ✅ Correct if this solves your issue and also mark ???? Helpful if you find my response worthy based on the impact.
Thanks,

[Community Alums]

Getting error in console getSCAttachmentCount is not defined.