在javascript版本的处理中打印出错误消息

To make a long story short I have to use processing in a class and I'm completely blind. The ide is completely inaccessible so I use the JavaScript version of processing to create a page and have a sited person describe the output to me. Unfortunately if the code has errors the page appears blank and there is no explanation of what’s wrong. Given the following code is there a way for the JavaScript version of processing to tell me that I have a syntax error since I forgot );To make a long story short I have to use proces