Provides a way to easily construct a set of key/value pairs representing
form fields and their values, which can then be easily sent using the
XMLHttpRequest.send() method. It uses the same format a form would use if the
encoding type were set to "multipart/form-data".
  
  
    
  
    
  
    
  
    
 
delete(name: string): void
      
    
get(name: string): FormDataEntryValue | null
      
    
getAll(name: string): FormDataEntryValue[]
      
    
has(name: string): boolean