Why are there so many warnings in Firefox DevTools and Firebug?

Question

I have a lot of warnings in Firefox and Firebug console. I don’t know what to do with them. It's my fault? Also, how can I make debugging understandable and useful in Firefox?

Here are some examples:

[11: 06: 16.845] cf function does not always return @ http://example.hu/jquery.js:16 [11: 06: 16.853] function ce does not always return @ http://example.hu/jquery .js: 16 [11: 06: 16.861] the bZ function does not always return the value @ http://example.hu/jquery.js:16 [11: 06: 16.870] the test for equality (==) was mistakenly accepted as an assignment ( =)? @ http://example.hu/jquery.js:16 [11: 06: 16.880] function M does not always return the value @ http://example.hu/jquery.js:16 [11: 06: 16.889] anonymous function does not always return @ http://example.hu/jquery.js:16 [11: 06: 16.921] test for equality (==) is mistakenly accepted as an assignment (=)? @ http://example.hu/jquery.js:16 [11: 06: 16.934] an anonymous function does not always return the value @ http://example.hu/jquery.js:16 [11: 06: 16.957] test for is equality (==) mistaken as assignment (=)? @ http://example.hu/jquery.js:16 [11: 06: 16.972] an anonymous function does not always return the value @ http://example.hu/jquery.js:17 [11: 06: 16.998] test for is equality (==) mistaken as assignment (=)? @ http://example.hu/jquery.js:17 [11: 06: 17.012] an anonymous function does not always return the value @ http://example.hu/jquery.js:17 [11: 06: 17.035] test for is equality (==) mistaken as assignment (=)? @ http://example.hu/jquery.js:17 [11: 06: 17.051] an anonymous function does not always return the value @ http://example.hu/jquery.js:17 [11: 06: 17.073] test for is equality (==) mistaken as assignment (=)? @ http://example.hu/jquery.js:17 [11: 06: 17.086] an anonymous function does not always return the value @ http://example.hu/jquery.js:17 [11: 06: 17.126] test for is equality (==) mistaken as assignment (=)? @ http://example.hu/jquery.js:18 [11: 06: 17.153] an anonymous function does not always return the value @ http://example.hu/jquery.js:18 [11: 06: 17.175] link to undefined property f.valHooks [this] @ http://example.hu/jquery.js:16 [11: 06: 17.208] reference to the undefined property a [f.expando] @ http://example.hu/jquery. js: 16 [11: 06: 17.376] reference to the undefined property a [f.expando] @ http://example.hu/jquery.js:16 [11: 06: 17.480] reference to the undefined property a [f.expando ] @ http://example.hu/jquery.js:16 [11: 06: 17.613] link to the undefined property f.event.triggered @ http://example.hu/jquery.js:16

reference to undefined property fbs.breakOnDebugCall [Break On This Error] var hookReturn = d...e, errorInfo, fbs.breakOnDebugCall); firebu...vice.js (line 1857) <System> reference to undefined property a[f.expando] [Break On This Error] (function(a,b){function cv(a){return f...ndexOf(".")>=0&&(i=h.split("."),h=i. jquery.js (line 16) reference to undefined property fbs.breakOnDebugCall [Break On This Error] return this.breakOnErrors || fbs.breakOnDebugCall; firebu...vice.js (line 3523) <System> reference to undefined property fbs.breakOnDebugCall [Break On This Error] var hookReturn = d...e, errorInfo, fbs.breakOnDebugCall); firebu...vice.js (line 1857) <System> reference to undefined property a[f.expando] [Break On This Error] (function(a,b){function cv(a){return f...ndexOf(".")>=0&&(i=h.split("."),h=i. jquery.js (line 16) reference to undefined property fbs.breakOnDebugCall [Break On This Error] return this.breakOnErrors || fbs.breakOnDebugCall; firebu...vice.js (line 3523) <System> reference to undefined property fbs.breakOnDebugCall [Break On This Error] var hookReturn = d...e, errorInfo, fbs.breakOnDebugCall); firebu...vice.js (line 1857) <System> reference to undefined property a[f.expando] [Break On This Error] (function(a,b){function cv(a){return f...ndexOf(".")>=0&&(i=h.split("."),h=i. jquery.js (line 16) reference to undefined property fbs.breakOnDebugCall [Break On This Error] return this.breakOnErrors || fbs.breakOnDebugCall; firebu...vice.js (line 3523) <System> reference to undefined property fbs.breakOnDebugCall [Break On This Error] var hookReturn = d...e, errorInfo, fbs.breakOnDebugCall); firebu...vice.js (line 1857) <System> reference to undefined property a[f.expando] [Break On This Error] (function(a,b){function cv(a){return f...ndexOf(".")>=0&&(i=h.split("."),h=i. 

Answer 1

What you can do to avoid logging in to the console is to clear the Strict Warnings checkbox.

Answer 2

Set javascript.options.strict to false in Firefox about: config