WordPress responsive captions

gistfile1.php

<?php
function dap_responsive_img_caption_filter( $val, $attr, $content = null ) {
	extract( shortcode_atts( array(
		'id' => '',
		'align' => '',
		'width' => '',
		'caption' => ''
		), $attr
	) );
	
	if ( 1 > (int) $width || empty( $caption ) )
		return $val;

	$new_caption = sprintf( '<div id="%1$s" class="wp-caption %2$s" style="max-width:100% !mportant;height:auto;width:%3$dpx;">%4$s<p class="wp-caption-text">%5$s</p></div>',
		esc_attr( $id ),
		esc_attr( $align ),
		( 10 + (int) $width ),
		do_shortcode( $content ),
		$caption
	);
	return $new_caption;
}

add_filter( 'img_caption_shortcode', 'dap_responsive_img_caption_filter', 10, 3 );