public function content( $atts ) {
		$script_handle = 'invp-iframe-resizer';
		if ( ! wp_script_is( $script_handle, 'registered' ) ) {
			Inventory_Presser_Plugin::include_scripts_and_styles();
		}
		wp_enqueue_script( $script_handle );
		wp_add_inline_script( $script_handle, 'iFrameResize({ log:false,sizeWidth:true });' );

		$atts = shortcode_atts(
			array(
				'width'       => '100%',
				'height'      => '5000',
				'scrolling'   => 'yes',
				'src'         => '',
				'class'       => 'iframe-class',
				'frameborder' => '0',
				'title'       => '',
			),
			$atts
		);

		// Stock number may arrive in a querystring variable with key 'stock'.
		if ( isset( $_GET['stock'] ) ) {
			$atts['src'] = esc_url( add_query_arg( 'stock', sanitize_text_field( wp_unslash( $_GET['stock'] ) ), $atts['src'] ) );
		}

		$html = '<iframe';
		foreach ( $atts as $attr => $value ) {

			// ignore some attributes.
			$ignored_atts = array(
				'onclick',
				'onload',
				'onpageshow',
				'same_height_as',
			);
			if ( in_array( strtolower( $attr ), $ignored_atts, true ) ) {
				continue;
			}

			if ( '' !== $value ) { // adding all attributes.
				$html .= ' ' . esc_attr( $attr ) . '="' . esc_attr( $value ) . '"';
			} else { // adding empty attributes.
				$html .= ' ' . esc_attr( $attr );
			}
		}
		$html .= '></iframe>';

		if ( isset( $atts['same_height_as'] ) ) {
			$html .= sprintf(
				'<script>
				document.addEventListener("DOMContentLoaded", function(){
					var target_element, iframe_element;
					iframe_element = document.querySelector("iframe.%s");
					target_element = document.querySelector("%s");
					iframe_element.style.height = target_element.offsetHeight + "px";
				});
				</script>',
				esc_attr( $atts['class'] ),
				esc_attr( $atts['same_height_as'] )
			);
		}

		return $html;
	}