javascript - If a page is blank after opening, how would you locate the problem? If it's not a network or server problem, it's a front-end problem. How to locate it?

Just now, I saw an interview question and I didn’t know how to answer it. I don’t know what everyone thinks. Thank you so much.

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Just now, I saw an interview question and I didn’t know how to answer it. I don’t know what everyone thinks. Thank you so much.

Check the status code returned by the page in the browser developer tools. If it is a 500 series, it is a server error. You can check the error log of the web server to find out where the error is. If the 200 return is successful, you can look at the console below. Is there any error message to determine if there is a problem with the js? You can also check the page source code to see if there is any content. Of course, the possibility of discovering the problem is unlikely

1.Frontend Analysis:open the chrome dev tool,record the http[s] proccess,then you will get the http status code;
2.Backend Analysis: grep nginx error log or access log,grep the unexpected http request,then get it.

js blocking?
If external js is introduced in and the execution time is long, the page should be blank at this time. The page, that is, the part, cannot be displayed until the external file in is loaded and executed.

Check the resource loading status to determine if there is a network or server problem. Check if there is any js error and the page is stuck loading. See the page source code.

If it is a front-end problem, there are many types of errors, such as script loading errors, js code problems, etc. If it is a resource loading problem, it should be able to detect it from the browser developer tools and prescribe the right remedy. If it is a problem in the code, there are many solutions. Try...catch is a relatively simple and commonly used method. That's all I know.

My own solution, but I don’t know if it’s suitable as an interview answer. Please forgive me if it’s unreasonable.

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1. First of all, if I wrote it myself, there was already a page. After writing some code, if I refresh the browser again and a blank page appears, I will copy the entire code that I just wrote, and then delete it on the original page. Yes, check whether it is good or not. If it is good, check the new code and then put it into the main code.

2. Secondly, if you have written a lot of code and don’t know where the problem is, first open the page and check whether the tags are complete, whether the links in the head part are correct, whether the js order is correct, and whether there are conflicts.

3. When writing JS, I personally use two browsers, ff and Google. When something goes wrong, I will use F12 to see if the console reports an error. I usually use console.log().alert() for debugging.