Editing Javascript debug

<< [[Testing]]: [[Javascript]]

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== Steps of troubleshooting ==
* Were the required js fils were included?

* Was the function was conflict with different js libraries? e.g. [https://stackoverflow.com/questions/41961708/uncaught-typeerror-tooltip-is-not-a-function javascript - Uncaught TypeError: $(...).tooltip is not a function - Stack Overflow]

* Checking the typo or "ensure that there are no compile-time errors"<ref>[https://stackoverflow.com/help/mcve How to create a Minimal, Complete, and Verifiable example - Help Center - Stack Overflow]</ref> by using [https://www.jslint.com/ JSLint] or other [[Javascript debug#tools | tools]].

* Verify the format of JSON file if the file was used by javascript by using [https://jsonlint.com/ JSONLint - The JSON Validator] tools.

* Disable the browser extension e.g. switch to '''incognito window''' on {{Chrome}}

* Quit the browser helper software e.g. video downloader

* Clear or disable the browser cache<ref>[https://www.java.com/zh_TW/download/help/webcache.xml 我要如何清除網頁瀏覽器快取？]</ref>

* Reload the webpage again

* Switch to different network environment

== Methods/Functions to Help with Debugging ==

Print message
* alert() Method: [https://www.w3schools.com/jsref/met_win_alert.asp Window alert() Method] equivalent: window.alert("some message...");
* [http://stackoverflow.com/questions/323517/is-there-an-equivalent-for-var-dump-php-in-javascript Is there an equivalent for var_dump (PHP) in Javascript? - Stack Overflow]
* console.log()
** {{Fx}}: [http://getfirebug.com/logging Firebug and Logging : Firebug], [http://ithelp.ithome.com.tw/question/10000465 利用Firebug的console功能作JavaScript偵錯 - iT邦幫忙::IT知識分享社群] for {{Fx}} {{exclaim}} not work for the [https://chrome.google.com/webstore/detail/firebug-lite-for-google-c/bmagokdooijbeehmkpknfglimnifench Firebug Lite for Google Chrome](tested version: 1.4.0.11967 )
** {{Chrome}}: [https://developers.google.com/chrome-developer-tools/docs/console Using the Console - Chrome Developer Tools — Google Developers] Enter the javascript scripts in the console ( after the {{kbd | key = <nowiki>></nowiki>}} symbol) directly.
* [http://blog.longwin.com.tw/2007/07/javascript_var_dump_2007/ Javascript var_dump function | Tsung's Blog]
* [https://www.w3schools.com/js/js_json_stringify.asp JSON.stringify()][https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify] "Convert a JavaScript object into a string" {{access | date = 2017-09-11}}

DOM
* 如果是進行 DOM 操作，可以將選定的 DOM 元素標上顏色，確認有選到。 ex: using [http://api.jquery.com/addClass/ .addClass() | jQuery API Documentation]

Data type
* [http://www.w3schools.com/jsref/jsref_isnan.asp isNaN() Function], [http://www.w3schools.com/jsref/jsref_isfinite.asp isFinite() Function], typeof variable

Browser tool
* [https://stackoverflow.com/questions/10213703/how-do-i-view-events-fired-on-an-element-in-chrome-devtools javascript - How do I view events fired on an element in Chrome DevTools? - Stack Overflow] on {{Chrome}}

Browser cache issue
* [https://stackoverflow.com/questions/44958022/managing-browser-cache javascript - Managing browser cache - Stack Overflow]
* [https://blog.miniasp.com/post/2008/02/03/Avoid-browser-cache-problem-on-css-or-javascript-file.aspx The Will Will Web | 簡易克服 CSS 被瀏覽器快取(Cache)的問題]

== tools ==
* [http://www.jslint.com/ JSLint,The JavaScript Code Quality Tool]
** desktop editor: [http://www.sublimetext.com/ Sublime Text] + package: JSLint<ref>[http://opensourcehacker.com/2012/04/12/jslint-integration-for-sublime-text-2/ JSLint integration for Sublime Text 2]</ref>
* [http://jsbin.com/ JS Bin - Collaborative JavaScript Debugging] {{Gd}} allow to download


== Further reading ==
* [https://errerrors.blogspot.com/2021/04/how-to-debug-javascript.html 怎樣對 JavaScript 進行偵錯] 

== References ==
<references/>

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[[Category: Programming]]
[[Category: Web_Dev]]
[[Category: Javascript]]