How to fix the validator error?

Question

Validation

Hello good people!
I decided to check the site hatiko58.ru for validity.
I found 39 errors, I fixed 29 myself, 10 left.
Help me, kind people.
MODx engine
Here are the errors:
Line 273, Column 100: cannot generate system identifier for general entity "hide_avatars"
…recent_comments_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_le…
Error Line 273, Column 100: general entity "hide_avatars" not defined and no default entity
…recent_comments_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_le…
Warning Line 273, Column 112: reference not terminated by REFC delimiter
…nts_widget.js?num_items=3&hide_avatars=1&avatar_size=24&
Warning Line 273, Column 112: reference to external entity in attribute value
…nts_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">…
Error Line 273, Column 112: reference to entity "hide_avatars" for which no system identifier could be generated
…nts_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">…
Info Line 273, Column 99: entity was defined here
…/recent_comments_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_l…
Warning Line 273, Column 115 : cannot generate system identifier for general entity "avatar_size"
…_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">…
Error Line 273, Column 115: general entity "avatar_size" not defined and no default entity
…_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">…
Warning Line 273, Column 126: reference not terminated by REFC delimiter
…dget .js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Warning Line 273, Column 126: reference to external entity in attribute value
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Error Line 273, Column 126 : reference to entity "avatar_size" for which no system identifier could be generated
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Info Line 273,Column 114: entity was defined here
…s_widget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">…
Warning Line 273, Column 130: cannot generate system identifier for general entity "excerpt_length"
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Error Line 273, Column 130: general entity "excerpt_length" not defined and no default entity
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Warning Line 273, Column 144: reference not terminated by REFC delimiter
…dget. js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Warning Line 273, Column 144: reference to external entity in attribute value
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Error Line 273, Column 144: reference to entity "excerpt_length" for which no system identifier could be generated
…dget.js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Info Line 273, Column 129: entity was defined here
…dget .js?num_items=3&hide_avatars=1&avatar_size=24&excerpt_length=200">
Error Line 282, Column 81: value of attribute "method" cannot be "POST"; must be one of "get", "post"
…rm action="/resultatyi-golosovaniya.html?poll=1" name="ap_form1" method="POST">
Error Line 299, Column 153: there is no attribute " data-yashareL10n"
…="yashare-auto-init" data-yashareL10n="en"
…ata-yashareL10n="en" data-yashareType="button" data-yashareQuickServices="vkon…
Error Line 299, Column 210: there is no attribute "data-yashareQuickServices"
…pe="button" data-yashareQuickServices="vkontakte ,facebook,twitter,odnoklassnik…