The Content Type field is a special field that only appears once multiple content types have been enabled on a list.
{code:javscript} // On EditForm, a Content Type field is displayed but it won't be available on NewForm // If you try to get the field on NewForm, an exception will be thrown and then logged below var field = SPUtility.GetSPField('Content Type');
// Hide the field
field.Hide();
// Make the field read only
//field.MakeReadOnly();
// Set the value using the display name
field.SetValue('Item');
// ... or the content type ID!
field.SetValue('0x0100DBD234B62463314F8DE3C4AA2635CD51');
// Setting the value does not force the page postback
// if you want to trigger the postback, use the Dropdown onchange
field.Dropdown.onchange();
{code:javscript}
Check out a code example here: https://github.com/kitmenke/sputility/blob/master/examples/contenttype.html.