How do you use the ? : (conditional) operator in JavaScript?
2011年6月7日 · It's a little hard to google when all you have are symbols ;) The terms to use are "JavaScript conditional operator". 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.
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. 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 .
What is the purpose of the dollar sign in JavaScript?
2022年3月29日 · Unlike many similar languages, identifiers (such as functional and variable names) in Javascript can contain not only letters, numbers and underscores, but can also contain dollar signs. They are even allowed to start with a dollar sign, or consist only of a dollar sign and nothing else. Thus, $ is a valid function or variable name in Javascript.
What does ${} (dollar sign and curly braces) mean in a string in ...
2016年3月7日 · I haven't seen anything here or on MDN. I'm sure I'm just missing something. There's got to be some documentation on this somewhere.
Difference between == and === in JavaScript - Stack Overflow
2009年2月7日 · 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 - What does [object Object] mean? - Stack Overflow
In JavaScript there are 7 primitive types: undefined, null, boolean, string, number, bigint and symbol. Everything else is an object. Everything else is an object. The primitive types boolean , string and number can be wrapped by their object counterparts.
JavaScript math, round to two decimal places - Stack Overflow
This is the actual correct answer. I'd just add that for the specific discount scenario, the simplified code would be: var discount = Math.round(10000 * (1 - price / listprice)) / 100; @ChristopheRoussy, the example you provided is actually correct and this result is caused by the fact that base-2 floating point can't represent all base-10 decimals precisely.
How to use OR condition in a JavaScript IF statement?
2010年3月2日 · In JavaScript, if you're looking for A or B, but not both, you'll need to do something similar to:
javascript - Check if an element is present in an array - Stack …
This is noted on the page, but it's worth mentioning as part of the answer: indexOf is a relatively new addition to JavaScript, and is not supported in IE version prior to 9.0. Also worth noting that indexOf will still be O(n), so if the OP meant "better" in terms of speed/performance this won't really be any better, just shorter.
JavaScript hide/show element - Stack Overflow
function showStuff(id, text, btn) { document.getElementById(id).style.display = 'block'; // hide the lorem ipsum text document.getElementById(text).style.display ...