Uncaught TypeError:Cannot read property ‘getContext’ of null

Question

Im getting this error: Uncaught TypeError: Cannot read property 'getContext' of null in my demo.js page I have included demo.js page in my html page (start page) . How can i solve this error?

Manoj Bhoir · Answer

I guess the problem is your js runs before the html is loaded. If you are using jquery, you can use the document ready function to wrap your code: $( function () { // codes... }); Or simply put your js after the

Laxmidhar Sahoo · Answer

I thinkmanoj is currect $(function() { var Grid = function () { var canvas = document .getElementById("canvas"); if(canvas.getContext) { var context = canvas .getContext("2d"); } } });

Bryian Tan · Answer

Tough to tell without any code.

Afzaal Ahmad Zeeshan · Answer

But you have not shared any of the code samples that you have used to develop the application. My guess is that you are trying to use the HTML5 canvas element to render something on top of it, in that case the variable that is holding the reference of your canvas is null. Make sure that the canvas element (or whatever element that has this getContext() function) exists in the DOM. var canvas = document.getElementById( "canvas" ); if (canvas != null ) { // do here. canvas.getContext( "2d" ); } else { // report the error. } This way you can resolve this problem. Do share the code if that doesn't fix the problem.

Uncaught TypeError:Cannot read property ‘getContext’ of null

Answers (4)