One of the Best feature to use in custom column rendering in sharepoint 2013.
How we can implement.
‘View’ function to render the field if it is included in a list view. In this function you return html.
‘DisplayForm’ function to render the field when the user is viewing the properties of a list item. Also returns html.
‘EditForm’ function to render the field when the user is editing the properties of a list item. Returns html.
‘NewForm’ function to render the field when the user is adding a new list item. Again, should return html. Normally this would be the same as the ‘EditForm’ but it doesn’t have to be.
‘GetValueCallBack’ function to pass the field’s value to SharePoint after the user clicks
Submit. This one should return the value type of the field type. In my example, I’ll return
a string value.The first step is to determine how you want the user to enter data. In the EditForm and
Next determine how you want your value passed back to SharePoint. There are a few options to
handle this. One option is to render a hidden input element when you render your data
capture. Then handle events on the data capture elements (e.g. onchange). Within the event
handlers populate the hidden input field’s value. In the end, pass the hidden input’s value to SharePoint in the getValueCallBack function.