FormData.has()

The has() method of the FormData interface returns a boolean stating whether a FormData object contains a certain key.

name

A string representing the name of the key you want to test for.

A boolean value.

The following line creates an empty FormData object:

var formData = new FormData();

The following snippet shows the results of testing for the existence of username in the FormData object, before and after appending a username value to it with FormData.append:

formData.has('username'); // Returns false
formData.append('username', 'Chris');
formData.has('username'); // Returns true

• XMLHTTPRequest
• Using XMLHttpRequest
• Using FormData objects
• <form>