brotherton-erpnext/docs/dev/custom_script_examples/docs.dev.custom_script.validate3.md

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Restrict Cancel Rights based on Certain Order Value

Add a handler to custom_before_cancel event:

cur_frm.cscript.custom_before_cancel = function(doc) {
    if (user_roles.indexOf("Accounts User")!=-1 && user_roles.indexOf("Accounts Manager")==-1
            && user_roles.indexOf("System Manager")==-1) {
        if (flt(doc.grand_total) > 10000) {
            msgprint("You can not cancel this transaction, because grand total \
                is greater than 10000");
            validated = false;
        }
    }
}