Why should I deregister jquery?

Linking jquery code twice conflicts the functions as they are present twice. So deregistering helps you but it is not good choice. You should go through jQuery no conflict thing. And you should register your jquery version with different name, so that it does not break wordpress.

Ref- jQuery Forum and Documentation

Related Posts:

  1. Enqueue core jQuery in the footer?
  2. How to correctly include jquery-ui effects on wordpress
  3. Concatenate and minify dependencies for enqueued JavaScript files
  4. tinymce is not defined when not using wp_editor
  5. Make jQuery library load before plugin files
  6. Adding jquery and thickbox to WordPress theme
  7. Move WordPress native javascript to bottom of page?
  8. RequireJS in custom theme. Working Example
  9. Add `datetimepicker` to form
  10. Deregister WordPress jquery on specific page
  11. Gravity Forms loading jquery
  12. Including javascript for a shortcode
  13. Best Way to Include Scripts on a Specific Template Page
  14. How to include jquery validate in a template
  15. wp_enqueue_script won’t load in header?
  16. chosen jquery library not loading – is not a function error
  17. wp_enqueuescript won’t load in footer even with true value set?
  18. How wp_enqueue_script works?
  19. Enqueue jQuery in WordPress
  20. WordPress Script Loading/Unloading — wp_deregister_script(‘jquery’)
  21. How do I activate jQuery/script on demand?
  22. Adding jQuery dependency prevents my script from enqueuing/loading
  23. How do I get my page to load the jQuery UI Effects library?
  24. Simple jQuery Click Not Working, though console log recognizes the function [closed]
  25. Script won’t execute in the media manager
  26. How to properly add Bootstrap and JQuery Javascripts?
  27. Can’t move jQuery to footer
  28. Using multiple versions of jQuery while still calling it like WP likes
  29. wp_ajax() question.. not using wp_enqueue_script?
  30. wp_enqueue_scripts hook is not being called
  31. Why isn’t jQuery 2.1 loading in the header?
  32. Override default jquery ui library with newer version
  33. enqueue the scripts
  34. Enqueuing javascript files
  35. WordPress loads Jquery Automatically – is my idea correct to add it to the footer?
  36. enqueued script with jquery dependency not getting jquery
  37. Enqueue Google CDN jQuery in Footer
  38. How to undo deregister script and use local versions?
  39. ‘jQuery is not defined Error’ appearing in load-scripts.php
  40. Is it necessary to enqueue jquery?
  41. WordPress Ajax problem with undefined url
  42. Enqueue WordPress jQuery after it’s been deregistered by a plugin
  43. Move jQuery to the bottom of the page whilst keeping the WordPress jQuery
  44. Exclude some scripts from removing unique scripts from head function
  45. Searching multiple tags and adding jQuery dependant script onto page template?
  46. How to enqueue jquery in admin and why is it not already there?
  47. Enque Javascript in Footer?
  48. Plugins loading multiple copies of JQuery
  49. Why is my WordPress loading old version of JQuery?
  50. Cannot enqueue jQuery correctly using Google CDN
  51. wp_enqueue doesn’t work
  52. Yoast SEO breaking media upload
  53. $.browser Undefined Seemingly Causing Faulty Page Display
  54. How register library to use jquery correct
  55. Trouble enqueueing jquery with custom theme
  56. Plugin Scripts no loading on options page
  57. How to enque js script in footer that are not in .js file?
  58. Loading scripts on a single page plants the script in the footer
  59. registering new jQuery after wp_deregister_script() not working
  60. Loading a newer version of jQuery within WordPress
  61. Run JS function when JQ enqueued
  62. jQuery will not work on page from snippet or file
  63. jQuery plugin not loading
  64. Can’t execute jQuery before my script
  65. Why does deregistering jQuery cause other scripts not to load?
  66. jQuery is not defined, working on local server but not online
  67. Using WP functions inside javascript
  68. Including Older Version of jQuery for IE7/IE8
  69. wp_enqueue_script jquery and jquery ui not working
  70. wp_enqueue_script calling jQuery at different times for different browsers?
  71. Calling multiple scripts using wp_enqueue_script
  72. WordPress not showing jQuery
  73. Get with jQuery the value of an ACF field
  74. Override parent theme deregister
  75. How to make JQuery load on top of head tag before everything
  76. jQuery Plugin Uncaught TypeError: jQuery(…).slider is not a function
  77. JavaScript code do not works on online server
  78. I can’t enqueue Suggest.js in frontend – not added
  79. File not enqueueing
  80. Enqueue script, taking no effect [closed]
  81. WordPress and Raty.js
  82. Can’t seem to get JQuery working (wordpress plugin)
  83. Enqueue javascript that inserts custom php widget into jQuery-constructed div
  84. Ajax Request with jQuery not happening
  85. jQuery AJAX add json2 dependency?
  86. jQuery does not appear to be enqueued on static homepage
  87. Uncaught TypeError: Object [object Object] has no method ‘dialog’
  88. Object [object Object] has no method ‘slides’
  89. Need help with adding jQuery script to WP and calling script to page
  90. How to Run a jQuery Script after a Javascript Script has Finished in WordPress
  91. How to make jQuery load AFTER plugin’s script?
  92. Monarch JS has not been loaded. After changing the $dep parameter, it start being loaded
  93. Can’t get jQuery to enqueue into post edit script
  94. javascript not loading in wordpress
  95. jQuery issue and wp_enqueue_script
  96. Using WP Ajax and jQuery to process multiple forms on the same page?
  97. bootstrap-slider.js by seiyria not working in wordpress
  98. How to enqueue script before jQuery? [duplicate]
  99. javascript and css not loading properly in WordPress site
  100. Making the Google Maps API non readable
error code: 523