Quick ways to find errors when web development pages go wrong

Recently in the modification of a JSP page, repeated the error, try to replace all the code, compiled n times or error, depressed the extreme.

Because my page calls JS written in a separate JS file, the browser error line number is dentures, according to the number of lines to find errors can only waste time.

My JS function of a total of hundreds of lines, repeated debugging unsuccessful, simply heart a horizontal, all the JS code all put on the page, do not write to the JS file, and then try again, at this time the browser error line number is right. Depending on the error line number, you can quickly locate the error and modify the error.

After debugging successfully, then put JS into a separate file.

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