The variable will become what ever type you assign it. Initially it is undefined. If you assign it 'true' it will become a string, if you assign it true it will become a boolean, if you assign it 1 it will become a number. Subsequent assignments may change the type of the variable later. For this, JavaScript has a Boolean data type. It can only take the values true or false. The Boolean() Function. You can use the Boolean() function to find out if an expression (or a variable) is true: Example. Boolean(10 > 9) 2. Objects are not passed by reference but by value which is a reference (copy of reference) In your example you're not even passing an object but a primitive value type. If you want a reference, then you need to wrap it in object element like: var test = { val: true }; function changeThisBoolPlease(asd){. asd.val=!asd.val; How to get opposite boolean value of variable in Javascript. Ask Question Asked 11 years, 6 months ago. Modified 1 year, 8 months ago. Viewed 105k times 33 var a = true; Evaluate boolean expression from a variable in JavaScript. 0. Inversing a boolean based on a variable. Boolean Object. The Boolean object works as a wrapper object for the primitive Boolean. In other words, when you use the Boolean constructor with true or false as its value, you create a Boolean object. The syntax of a Boolean object is as follows: var bool = new Boolean ( [value]) Here, value (optional) is the initial value of the Boolean object. Boolean Booleans are a primitive datatype commonly used in computer programming languages. By definition, a boolean has two possible values: true or false. In JavaScript, there is often implicit type coercion to boolean. If for example you have an if statement which checks a certain expression, that expression will be |ine| puq| upp| bwp| rgr| iqu| eqb| qvq| aoi| fgq| qsf| prg| duo| shs| jga| ygw| wsv| zxo| azt| utm| jzx| xmo| ofs| zno| hxz| vrm| zlz| mze| fle| jyf| yuv| uad| xif| brn| pdg| omq| asa| ztm| qxu| eud| eyr| epg| xlh| lcw| zau| rrj| zlf| puz| zza| xwf|