1, the wrong call in the HTML JS file, and then use the browser to open, F12 on the keyboard open press, open the debugging tool, opens, we see the top right corner of the console-left position, as indicated by arrows, in this place is displayed JS code has several errors.
2, find the Console option console, click with the left mouse button, as has been pointed arrow.
3. Click the file name, navigate to the location of the code.
4, in which the code editor targeted modification JS code.