User:Theleekycauldron/sandbox.js

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This user script seems to have a documentation page at User:Theleekycauldron/sandbox.

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var params = {
		action: 'edit',
		title: 'User:Theleekycauldron/sandbox',
		text: 'Hello',
		format: 'json'
	},
	api = new mw.Api();

api.postWithToken( 'csrf', params ).done( function ( data ) {
	console.log( data );
} );