{"id":20612,"date":"2022-11-10T06:22:22","date_gmt":"2022-11-10T00:52:22","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-non_existing_element-returns-in-console-but-referenceerror-when-called-as-a-variable-in-console-closed\/"},"modified":"2022-11-10T06:22:22","modified_gmt":"2022-11-10T00:52:22","slug":"solved-non_existing_element-returns-in-console-but-referenceerror-when-called-as-a-variable-in-console-closed","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-non_existing_element-returns-in-console-but-referenceerror-when-called-as-a-variable-in-console-closed\/","title":{"rendered":"[Solved] `$(“non_existing_element”);` returns `[ ]` in Console but `ReferenceError` when called as a variable in Console [closed]"},"content":{"rendered":"

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30<\/strike> 90 seconds about variable scoping<\/h1>\n
$(document).ready(function(){\n  var someVar = $(\"non_existing_element\");\n});\n<\/code><\/pre>\n
At this point, someVar<\/code> does, in fact equal []<\/code>. So if you were to write:<\/p>\n
$(document).ready(function(){\n  var someVar = $(\"non_existing_element\");\n  console.log(\"the value of someVar is\", someVar);\n});\n<\/code><\/pre>\n
You would see in your console <\/p>\n
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The value of someVar is []<\/p>\n<\/blockquote>\n
Hooray!<\/p>\n
But!<\/p>\n
As soon as you pass that last curly bracket…<\/p>\n
$(document).ready(function(){\n  var someVar = $(\"non_existing_element\");\n}); \/\/ <<<<< This one\n<\/code><\/pre>\n
You have left the function<\/strong> defined by function() {}<\/code>. Notice, it has no name, so this is called an anonymous<\/em> function. Don’t worry, it does not have a vendetta against politics or the economy.<\/p>\n
Once you leave the function, variables defined with var<\/code> are no longer accessible. This is to prevent scope leak<\/em>, which is a whole other conversation, which I’m sure you’ll be learning about very soon. Try defining it without var<\/code>. See what happens. <\/p>\n
Not using var<\/code> will allow the variable to escape the clutch of the wretched anonymous function, and crap itself all over your global scope. (which, by the way is accessible through window.global_variable<\/code>)<\/p>\n
So, when you type a variable into your console (does not apply if you’re using breakpoints<\/a>), variables are read from your global scope, since you are not inside<\/em> any function. And since we just discovered that var<\/code> scoped the variable to the function you’re not in, we now know why it is undefined.<\/p>\n
I mean, imagine if there could only be one variable named checkbox<\/code>! Every Javascript plugin you put in would conflict with each other. No one would know what checkbox<\/code> was, and before you know it, crazy stuff is happening all over your DOM.<\/p>\n
Moral of the story: Scope your variables. Understand your variables. Love your variables.<\/p>\n<\/p><\/div>\n
<\/div>\n<\/div>\n
            3<\/span> <\/p><\/div>\n<\/div>\n
[ad_2]<\/p>\n
solved `$(“non_existing_element”);` returns `[ ]` in Console but `ReferenceError` when called as a variable in Console [closed] <\/p>\n","protected":false},"excerpt":{"rendered":"
[ad_1] 30 90 seconds about variable scoping $(document).ready(function(){ var someVar = $(“non_existing_element”); }); At this point, someVar does, in fact equal []. So if you were to write: $(document).ready(function(){ var someVar = $(“non_existing_element”); console.log(“the value of someVar is”, someVar); }); You would see in your console The value of someVar is [] Hooray! But! As … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[388],"class_list":["post-20612","post","type-post","status-publish","format-standard","hentry","category-solved","tag-jquery"],"yoast_head":"\n[Solved] `$("non_existing_element");` returns `[ ]` in Console but `ReferenceError` when called as a variable in Console [closed] - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-non_existing_element-returns-in-console-but-referenceerror-when-called-as-a-variable-in-console-closed\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] `$("non_existing_element");` returns `[ ]` in Console but `ReferenceError` when called as a variable in Console [closed] - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] 30 90 seconds about variable scoping $(document).ready(function(){ var someVar = $("non_existing_element"); }); At this point, someVar does, in fact equal []. So if you were to write: $(document).ready(function(){ var someVar = $("non_existing_element"); console.log("the value of someVar is", someVar); }); You would see in your console The value of someVar is [] Hooray! But! As ... 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