How to display an input field mask?

Set the HTML placeholder attribute to the desired mask on the input field: 

<input type="text" name="FieldName" placeholder="dd/mmm/yyyy">

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Above code will display "dd/mmm/yyyy", to alert the user of format that should be typed into the field.

NOTES:

• The mask will disappear when the input field is under focus.
   
• This will not limit the format of the characters typed in. To achieve this, a 3rd party JavaScript library needs to be used.