In arcgis Online we can upload Geojson after logging into ArcGIS Online. Can we do the same thing from JavaScript using any api i.e we click on a button and the data should be pushed in content of ArcGIS online?
Are you looking to create a new item in your content? If so, I think you'd need to post a request to the ArcGIS REST API for content managment - specifically the addItem API. You could do this using the esriRequest function from the ArcGIS SDK for JavaScript (I'm not aware off-hand of a specific function for this in the SDK). You could also consider the createItem method provided by ArcGIS REST JS (a separate library).
