Which equals operator (== vs ===) should be used in JavaScript ...
2008年12月11日 · JavaScript has two sets of equality operators: === and !==, and their evil twins == and !=. The good ones work the way you would expect. If the two operands are of the same type and have the same value, then === produces true and !== produces false. The evil twins do the right thing when the operands are of the same type, but if they are of ...
What does the !! (double exclamation mark) operator do in …
The == and != operators do type coercion before comparing. This is bad because it causes ' \t\r\n' == 0 to be true. This can mask type errors. JSLint cannot reliably determine if == is being used correctly, so it is best to not use == and != at all and to always use the more reliable === and !== operators instead.
How do you use the ? : (conditional) operator in JavaScript?
2011年6月7日 · If you see any more funny symbols in JavaScript, you should try looking up JavaScript's operators first: Mozilla Developer Center's list of operators. The one exception you're likely to encounter is the $ symbol. To answer your question, conditional operators replace simple if statements. An example is best:
What is the JavaScript >>> operator and how do you use it?
Although JavaScript's Numbers are double-precision floats(*), the bitwise operators (<<, >>, &, | and ~) are defined in terms of operations on 32-bit integers. Doing a bitwise operation converts the number to a 32-bit signed int, losing any fractions and higher-place bits than 32, before doing the calculation and then converting back to Number.
What's the difference between & and && in JavaScript?
@Bludream: The explanation in this answer is wrong. You do not use bitwise operators for logical (boolean) comparisons. You use logical (boolean) operators. They do different (although similar) things, expect different inputs, produce different outputs, and have different operator precedence. –
comparison operators - Difference between == and === in …
2009年2月7日 · === and !== are strict comparison operators: JavaScript has both strict and type-converting equality comparison. For strict equality the objects being compared must have the same type and: Two strings are strictly equal when they have the same sequence of characters, same length, and same characters in corresponding positions.
JavaScript comparison operators: Identity vs. Equality
2016年8月9日 · I've been trying to understand the difference between JavaScript's comparison operators: identity and equality. From what I've read, if you check the equality of two objects using ==, JavaScript will try to figure out if they are the same type and, if not, try to get them to that same type. However, === doesn't behave in the same manner.
javascript - What is the difference between the `=` and `==` …
I would check out CodeCademy for a quick intro to JavaScript. If you prefer to read more, MDN is a great intro as well. For those concerned about the source of the term "identity operator" jbabey pointed out that JavaScript: The Definitive Guide seems to mention it.
The logical && and || operators in JavaScript - Stack Overflow
2016年12月18日 · In the first expression, c, d, and e are definitely not ignored (unless a or b was false and the expression short-circuited).
operators - What do ">>" and "<<" mean in Javascript? - Stack …
2011年8月9日 · These are the shift right and shift left operators. Essentially, these operators are used to manipulate values at BIT-level. They are typically used along with the the & (bitwise AND) and | (bitwise OR) operators and in association with masks values such as the 0x7F and similar immediate values found the question's snippet.