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How to check a not-defined variable in JavaScript
...nly be done with try/catch, since typeof will treat an undeclared variable and a variable declared with the value of undefined as equivalent.
But, to check if a variable is declared and is not undefined:
if (yourvar !== undefined) // Any scope
Previously, it was necessary to use the typeof opera...
Is there a JavaScript / jQuery DOM change listener?
... // ...
});
// define what element should be observed by the observer
// and what types of mutations trigger the callback
observer.observe(document, {
subtree: true,
attributes: true
//...
});
This example listens for DOM changes on document and its entire subtree, and it will fire on chang...
Remove ActiveRecord in Rails 3
...app I have just started work on in Rails 3 beta, both to get a feel for it and get a bit of a head-start. The app uses MongoDB and MongoMapper for all of its models and therefore has no need for ActiveRecord. In the previous version, I am unloading activerecord in the following way:
...
Remove Application Insight from application on Visual Studio 2013
...pplication insight to a project which creates a ApplicationInsights.config and not sure what other files were added to the project.
...
How do JavaScript closures work?
...nowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?
...
Infinity symbol with HTML
...resting results within 3 seconds, including utf8icons.com, fileformat.info and others.
– trejder
Jun 12 '14 at 11:00
@...
Determine the line of code that causes a segmentation fault?
...
Use bt as a shorthand for backtrace.
– rustyx
May 27 '19 at 7:53
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Is there a W3C valid way to disable autocomplete in a HTML form?
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Here is a good article from the MDC which explains the problems (and solutions) to form autocompletion.
Microsoft has published something similar here, as well.
To be honest, if this is something important to your users, 'breaking' standards in this way seems appropriate. For example, Ama...
Good NumericUpDown equivalent in WPF? [closed]
...another lacking control in WPF. There must be some existing ones out there and I don't like to re-invent the wheel.
9 Answe...
How can I get the source code of a Python function?
... tuple; tuple[0] is list of strings representing the lines of source code, and tuple[1] is the line number in the context of execution where it was run. In IPython; this is the line number within the cell not the overall notebook
– The Red Pea
Sep 23 '14 at 5:3...