Modify NewForm.aspx Sharepoint Online

Question

I'm new to SharePoint programming or modify form. I have a tenant with SharePoint Online and I created a list with calendar view: I'd like to modify the form when a user insert an event. I tried to load the site with SharePoint Designer 2013 and tried to create a new form but obtained the error dialog with message "Could not save the list changes to the server." After this, I tried to open the NewForm.aspx to see the code and maybe change it directly, but I can't see all the code: it seems that the part where there is the javascript is missing and there is a tag of missing assembly (sorry in the screenshot is in italian)

SPD missing assembly

So I tried with Visual Studio, but when I try to create a solution I obtain the error in the screeshot

VS create solution error

So the question is: I'm a beginner and I want to start with modify the NewForm.aspx so I can cancel some field to test: how to procede? I found many links and references but it seems that SharePoint Online have different behaviour versus the old and on premise editions.

Any idea in what mode I can procede?

Answer 1

Editing or exchanging the Newform.aspx is the old way of customizing the SharePoint UI. The more modern way (and the only one which makes sense with SharePoint Online at the time of writing) is to use the JSLink Technology.

With JSLink you can attach custom JavaScript Rendering Code to Content Types, Fields etc. Check out the JS Link Introduction and the JS Link Tutorial