I wrote a javascript method to create folder in google drive.
function createFolder(){
data = new Object();
data.title = 'New Folder';
data.parents = [{"id":jQuery('#parent').val()}];
data.mimeType = "application/vnd.google-apps.folder";
gapi.client.drive.files.insert(data).execute(function(fileList){});
}
It creates a file named 'Untitled' with mimeType "application/octet-stream" and parent root directory. This code supposed to create a folder named "New Folder".