Checking forNaNvalues in JavaScript can be tricky, becauseNaNis a special value that represents the result of an invalid or undefined mathematical operation.NaNstands for Not a Number, but its type is actually number. Therefore, we cannot use the usual equality operators (==or===) to compare ...
isVariableHaveDefaltVal(' '); // string isVariableHaveDefaltVal(false); // boolean var a; isVariableHaveDefaltVal(a); isVariableHaveDefaltVal(0); // number isVariableHaveDefaltVal(parseInt('')); // NAN isNAN(' '); - true isVariableHaveDefaltVal(null); isVariableHav...
3 How do I test for a empty string/null, using JavaScript? 16 How to check for empty value in Javascript? 0 How can I check if a variable is neither null or the empty string with javascript? 3 New to JavaScript, how to do a null check? 2 Comparing String to null ...
Is null false in JavaScript? Null is not considered false in JavaScript, but it is considered falsy. This means that null is treated as if it’s false when viewed through boolean logic. However, this is not the same thing as saying null is false or untrue. ...
isnan is-nan is-num is-number isnumber isfinite istype View more jonschlinkert •7.0.0•7 years ago•2,832dependents•MITpublished version7.0.0,7 years ago2832dependentslicensed under $MIT 334,675,466 is-gif Check if a Buffer/Uint8Array is a GIF image ...
How do you check if a variable is an array in JavaScript? How to check if a variable is an integer in JavaScript? How to check if a variable is NaN in JavaScript? How to check if a variable is boolean in JavaScript? How to check if a variable exists in JavaScript? How do we check...
Checking the data type of the value can be misleading. Read this tutorial and learn which operator is used to check if a value is an object in JavaScript.
<!DOCTYPE html> document.writeln(isNaN("blue")); document.writeln(isNaN("123")); <!-- w w w . j av a2 s . com--> Click to view the demoThe code above generates the following result.Next » « PreviousHome » Javascript ...
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check.number is part of the check-types library, but as a note, it does not pass null, undefined or NaN valuescheck.number(null); // false check.not.number(undefined); // true check.number(NaN); // falsecheck.emailReally simple regex email check. Should not be relied to be robust....