API Name: global.RecordAccessChecker

var RecordAccessChecker = Class.create();
RecordAccessChecker.prototype = Object.extendsObject(AbstractAjaxProcessor, {
canWrite: function() {
var table = this.getParameter("sysparm_table");
var sys_id = this.getParameter("sysparm_sys_id");
var gr = new GlideRecord(table);
if (!gr.get(sys_id))
return false;

return gr.canWrite();
},

type: 'RecordAccessChecker'
});