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How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?
140882
Proper way to detect empty/blank text
109927
JavaScript null check
5377
Is there a standard function to check for null, undefined, or blank variables in JavaScript?
148793
Checking Textbox Text for Null
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How to avoid returning a Null if there is no "else" condition in an If construct
104501
How do I enforce null checking?
43769
How do I Parameterize a null string with DBNull.Value clearly and quickly
38241
How do I check for nulls in an '==' operator overload without infinite recursion?
75247
Convert string to nullable type (int, double, etc...)
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.NET : How do you get the Type of a null object?
92055
In JavaScript, why is "0" equal to false, but when tested by 'if' it is not false by itself?
78285
How to check for equals? (0 == i) or (i == 0)
127800
SQL: Using NULL values vs. default values
120071
Checking for a null int value from a Java ResultSet
79162
Javascript null or empty string does not work
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Is there any difference between IS NULL and =NULL