Checking whether or not a node has been previously defined
55996
How can I know if a node is already defined?
102826
Easy way to check that a variable is defined in python?
6288
How do I check if an object has a specific property in JavaScript?
83782
How to check a not-defined variable in JavaScript
83533
Using the expression "the same" for a previously mentioned item
56390
How to detect if a function is called as constructor?
5307
Check if a variable is in an ad-hoc list of values
49446
How to check for an undefined or null variable in JavaScript?
89726
How to count the number of unique views of a node?
105864
How to check if element has any children in Javascript?
61188
How to recenter an object's origin?
86651
How to determine if Javascript object is an event?
21081
How to override a node using alias?
92688
Python: Determine if an unsorted list is contained in a 'list of lists', regardless of the order to the elements
30955
Check if a string contains an element from a list (of strings)
147859
How do I check if a table exists in sqlite3 c++ API?
100210
How to check if click event is already bound - JQuery