This script will help you to open media modal in wordpress.

WordpressMediaModal.js

// Very Simple Wordpress Image Uploader
jQuery(document).ready(function($) {
		var frame;
		$('#buttonID').on('click', function(event) {
				event.preventDefault();

				// Create a new media frame
				frame = wp.media({
					title: 'Select or Upload file Of Your Chosen Persuasion',
					button: {
						text: 'Use this file'
					},
					multiple: false
				});

				frame.on( 'select', function() {

						var attachment = frame.state().get('selection').first().toJSON();
						$('#element_id_or_class').val(attachment.url); //Set attachement URL to the input

				});

				frame.open();
		});
});