How can I auto trigger file input? ie. in the link below I want to trigger upload button on load
DEMO
Show input file dialog on load?
As described here only Internet Explorer allows for programmatic opening of the File Upload dialog. So the short answer is no, there is no way to automatically open the File Upload dialog on page load.
The long answer that you might consider is that you can show it when the user clicks on anything. The fact that you prefer an AngularJS solution tells us that you are writing a Single Page Application. Also, I don't think you need to show the File Upload dialog when the app first loads. You most likely need it to show after some user interaction - after the user clicks on something. That something, using the an AngularJS directive from here, could look like anything but be a file input. On click (the same user interaction) you can also switch to another route in your AngularJS app, effectively simulating a user navigating to another page and automatically presenting him the File Upload dialog.