Exemplo de escrita de arquivos usando phonegap

phonegap_plugin_file.js

	function writeFile22() {
		
		dataObj = "myfile.txt";
		
		window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function (fileEntry) {
			
			// Create a FileWriter object for our FileEntry (log.txt).
			fileEntry.createWriter(function (fileWriter) {
				
				fileWriter.onwriteend = function() {
				   alert("Successful file write...");
					readFile(fileEntry);
				};

				fileWriter.onerror = function (e) {
					alert("Failed file write: " + e.toString());
				};

				// If data object is not passed in,
				// create a new Blob instead.
				if (!dataObj) {
					dataObj = new Blob(['some file data'], { type: 'text/plain' });
				}

				fileWriter.write(dataObj);
			});
			
		}, function(){
			alert( "erro permissão");
		});

	}