Javascript：如何处理响应字符串解析中的语法错误

Question

In my HTML file, I have a single line (below) that gets a response from a device over WiFi & makes data available to my JavaScript, it works well except when there is an error in the response text & it halts.

<script type="text/javascript" src="http://192.168.4.1/"></script>

The response is a text string representing JavaScript variables, it sometimes gets corrupted throwing an error.

Examples:

Uncaught SyntaxError: invalid assignment left-hand side  192.168.4.1:14:3  
      SyntaxError: unterminated string literal  192.168.4.1:3:8

I need a solution to capture the error of parsing the received string so I can run the above statement again to get a new string.

Thanks

below is a picture of the response string (JS variables.)

The issue is that once the script is loaded, its content might be misformed and I would like to avoid having errors due to that.

Update #1. get the data with XMLHttpRequest

<script>
   const Http = new XMLHttpRequest();
   const url='http://192.168.4.1/';
    Http.open("GET", url);
  //  Http.setRequestHeader('Access-Control-Allow-Origin', '*');
    Http.send();
  ReturnVar = Http.responseText
  Http.onreadystatechange = (e) => { console.log(Http.responseText) }
</script>

Below is the detail in browser Console, Headers after script above run.

   GET
    scheme  http
    host        192.168.4.1
    filename    /
    Address 192.168.4.1:80
    Transferred 1.82 KB (1.82 KB size

Request headers (278B)  
GET / 
Host: 192.168.4.1
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: null
DNT: 1
Connection: keep-alive
Cache-Control: max-age=0

Answer 1

You have a script tag, which is loading the script and evaluating its content. You need to programmatically modify this, so you need to

Get the file as a text

https://www.freecodecamp.org/news/here-is-the-most-popular-ways-to-make-an-http-request-in-javascript-954ce8c95aaa/

You just need to programmatically download the content the file, not as the src of a script .

Evaluate it

Before you proceed, read this: https://javascriptweblog.wordpress.com/2010/04/19/how-evil-is-eval/

Now, that you know that eval is not exactly popular - and rightly so - and if you are still sure you need to run a script as it is, study eval and make it work equivalently as it was

Encapsulate it into try-catch

Example for error:

eval("'");

Example for error in try-catch:

try {eval("'")} catch (ex) {}

Answer 2

you can call the address using ajax, and then if the response is in json you can easily use it, but if its some sort of script or something else, wrap it in a script tag an append it to the body. assume the result is what you got from ajax request and you have jQuery in your project:

$('body').append('<script>'+result+'</script>')

in this case you can wrap your code in try catch and handle the errors