Use the following JavaScript to retrieve the current entity logical name and record ID in CRM Portal forms:
For Entity Form:
Entity logical name: $(“#EntityFormControl_EntityFormView_EntityName”).val()
Record ID: $(“#EntityFormControl_EntityFormView_EntityID”).val()
For Web Form Step:
Entity logical name: $(“#EntityFormView_EntityName”).val()
Record ID: $(“#EntityFormView_EntityID”).val()
Tested on xRM Portal CE.
UPDATE 10/01/2019:
The HTML structure is now different for Portal version 9.0.12.12 (cloud). There is now a GUID in the HTML field ID, e.g. EntityFormControl_978076ec8cf7e811a965000d3ae13a46_EntityFormView_EntityID.
For Entity Form, use the following:
- Entity logical name: $(“input[id^=’EntityFormControl_’][id$=’_EntityFormView_EntityName’]”).val()
- Record ID: $(“input[id^=’EntityFormControl_’][id$=’_EntityFormView_EntityID’]”).val()
- Record state: $(“input[id^=’EntityFormControl_’][id$=’_EntityFormView_EntityState’]”).val()
- Record status: $(“input[id^=’EntityFormControl_’][id$=’_EntityFormView_EntityStatus’]”).val()
Bernado Nguyen-Hoan's Blog - Coding Stories from an IT Mercenary 
Hi, Can I do Javascript that runs on submit of the form (Basic Form)? Something like;
$(#formid).submit(function () {
//do logic here
});
});
If so, how do I get the form id?
Thanks!