javascript string null
If you truly want to confirm that a variable is not null and not an empty string specifically, you would write: if(data !== null && data !==, The verbose method to check if value is undefined or null is: ..... Say, if a string is empty var name = "" then console.log(!name) returns true ., If you truly want to confirm that a variable is not null and not an empty string specifically, you would write: if(data !== null && data !==, The only values that are not truthy in JavaScript are the following (a.k.a. falsy ... I did an ajax call and got data back as null, in a string format., This means that String(null) and String(undefined) go into this special table of types and just return the string values valued "null" and ..., Use !value . It works for undefined , null and even '' value: var value = null; if(!value) console.log('null value'); } value = undefined; if(!value) ..., If you want to know if it's an empty string use === instead of ==. if(variable === "") } ... if(str == "" || str == null) //enter code here }. share|improve ..., If you need to check specifically for an empty string over null, I would think checking against "" is your best bet, using the === operator (so that ..., First, always use === instead of == in Javascript. ... This checks if the type of the value is "string" (and thus non-null and not undefined), and if it ...
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 javascript string null 相關參考資料
How to check if a value is not null and not empty string in JS ...
If you truly want to confirm that a variable is not null and not an empty string specifically, you would write: if(data !== null && data !== https://stackoverflow.com Is there a standard function to check for null, undefined, or ...
The verbose method to check if value is undefined or null is: ..... Say, if a string is empty var name = "" then console.log(!name) returns true . https://stackoverflow.com javascript - How to check if a value is not null and not empty string in ...
If you truly want to confirm that a variable is not null and not an empty string specifically, you would write: if(data !== null && data !== https://stackoverflow.com javascript - How to check if a variable is not null? - Stack Overflow
The only values that are not truthy in JavaScript are the following (a.k.a. falsy ... I did an ajax call and got data back as null, in a string format. https://stackoverflow.com javascript - Why does String(null) work? - Stack Overflow
This means that String(null) and String(undefined) go into this special table of types and just return the string values valued "null" and ... https://stackoverflow.com javascript check null or empty string - Stack Overflow
Use !value . It works for undefined , null and even '' value: var value = null; if(!value) console.log('null value'); } value = undefined; if(!value) ... https://stackoverflow.com Javascript: How to check if a string is empty? - Stack Overflow
If you want to know if it's an empty string use === instead of ==. if(variable === "") } ... if(str == "" || str == null) //enter code here }. share|improve ... https://stackoverflow.com null - How do you check for an empty string in JavaScript? - Stack ...
If you need to check specifically for an empty string over null, I would think checking against "" is your best bet, using the === operator (so that ... https://stackoverflow.com String.IsNullOrEmpty in JavaScript - Code Review Stack Exchange
First, always use === instead of == in Javascript. ... This checks if the type of the value is "string" (and thus non-null and not undefined), and if it ... https://codereview.stackexchan |