Places UI Kit: A ready-to-use library that provides room for customization and low-code development. Try it out, and share yourinput on your UI Kit experience.

Listening to Events

  • This example demonstrates creating a user-editable, draggable rectangle on a Google Map.

  • An info window dynamically displays the updated coordinates of the rectangle's northeast and southwest corners as the user adjusts it.

  • The sample code utilizes the Google Maps JavaScript API with event listeners and theRectangle class to achieve this functionality.

  • You can interact with a live version of this example via JSFiddle or Google Cloud Shell, or clone and run the sample locally using Git and Node.js.

This example adds a user-editable rectangle to the map. When the user changesthe bounds of the rectangle, an info window pops up displaying the new bounds.

Read thedocumentation.

TypeScript

// This example adds a user-editable rectangle to the map.// When the user changes the bounds of the rectangle,// an info window pops up displaying the new bounds.letrectangle:google.maps.Rectangle;letmap:google.maps.Map;letinfoWindow:google.maps.InfoWindow;functioninitMap():void{map=newgoogle.maps.Map(document.getElementById("map")asHTMLElement,{center:{lat:44.5452,lng:-78.5389},zoom:9,});constbounds={north:44.599,south:44.49,east:-78.443,west:-78.649,};// Define the rectangle and set its editable property to true.rectangle=newgoogle.maps.Rectangle({bounds:bounds,editable:true,draggable:true,});rectangle.setMap(map);// Add an event listener on the rectangle.rectangle.addListener("bounds_changed",showNewRect);// Define an info window on the map.infoWindow=newgoogle.maps.InfoWindow();}/** Show the new coordinates for the rectangle in an info window. */functionshowNewRect(){constne=rectangle.getBounds()!.getNorthEast();constsw=rectangle.getBounds()!.getSouthWest();constcontentString="<b>Rectangle moved.</b><br>"+"New north-east corner: "+ne.lat()+", "+ne.lng()+"<br>"+"New south-west corner: "+sw.lat()+", "+sw.lng();// Set the info window's content and position.infoWindow.setContent(contentString);infoWindow.setPosition(ne);infoWindow.open(map);}declareglobal{interfaceWindow{initMap:()=>void;}}window.initMap=initMap;
Note: Read theguide on using TypeScript and Google Maps.

JavaScript

// This example adds a user-editable rectangle to the map.// When the user changes the bounds of the rectangle,// an info window pops up displaying the new bounds.letrectangle;letmap;letinfoWindow;functioninitMap(){map=newgoogle.maps.Map(document.getElementById("map"),{center:{lat:44.5452,lng:-78.5389},zoom:9,});constbounds={north:44.599,south:44.49,east:-78.443,west:-78.649,};// Define the rectangle and set its editable property to true.rectangle=newgoogle.maps.Rectangle({bounds:bounds,editable:true,draggable:true,});rectangle.setMap(map);// Add an event listener on the rectangle.rectangle.addListener("bounds_changed",showNewRect);// Define an info window on the map.infoWindow=newgoogle.maps.InfoWindow();}/** Show the new coordinates for the rectangle in an info window. */functionshowNewRect(){constne=rectangle.getBounds().getNorthEast();constsw=rectangle.getBounds().getSouthWest();constcontentString="<b>Rectangle moved.</b><br>"+"New north-east corner: "+ne.lat()+", "+ne.lng()+"<br>"+"New south-west corner: "+sw.lat()+", "+sw.lng();// Set the info window's content and position.infoWindow.setContent(contentString);infoWindow.setPosition(ne);infoWindow.open(map);}window.initMap=initMap;
Note: The JavaScript is compiled from the TypeScript snippet.

CSS

/* * Always set the map height explicitly to define the size of the div element * that contains the map. */#map{height:100%;}/* * Optional: Makes the sample page fill the window. */html,body{height:100%;margin:0;padding:0;}

HTML

<html>  <head>    <title>Listening to Events</title>    <link rel="stylesheet" type="text/css" href="./style.css" />    <script type="module" src="./index.js"></script>  </head>  <body>    <div></div>    <!--       The `defer` attribute causes the script to execute after the full HTML      document has been parsed. For non-blocking uses, avoiding race conditions,      and consistent behavior across browsers, consider loading using Promises. See      https://developers.google.com/maps/documentation/javascript/load-maps-js-api      for more information.      -->    <script      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"      defer    ></script>  </body></html>

Try Sample

Clone Sample

Git and Node.js are required to run this sample locally. Follow theseinstructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

gitclone-bsample-rectangle-eventhttps://github.com/googlemaps/js-samples.gitcdjs-samplesnpminpmstart

Other samples can be tried by switching to any branch beginning withsample-SAMPLE_NAME.

gitcheckoutsample-SAMPLE_NAMEnpminpmstart

Except as otherwise noted, the content of this page is licensed under theCreative Commons Attribution 4.0 License, and code samples are licensed under theApache 2.0 License. For details, see theGoogle Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.

Last updated 2025-11-21 UTC.