how a variable’s type can be changed on-the-fly.

@KorFeb 21.2011 — #Well, strictly speaking, JavaScript has no typically methods to change the type of the variables, but it can parse/stringify some variables if their structure permits that. In some cases, when change it, it will return paradoxically typeof values ?

[B]parseInt()[/B] and [B]parseFloat()[/B] are, in fact parsing methods.

Let's take parseIn(). The full syntax is [B]parseInt([/B][I]value[/I],[I]base[/I][B])[/B], and it was design to parse an integer number from a [I]base to decimal[/I]

<i>
 </i>var decimalInt=parseInt('ff',16)
 alert(decimalInt) // returns 255, the decimal equivalent of the hexa number "FF"

Collaterally, it can be used to extract the decimal integer from a construction like "INT+STRING" like "25px". Or to extract the integer from a floated decimal like "INT.FLOAT" like "25.47". But this is not the main purpose of the method.

There is also the [B]Number([/B][I]value[/I][B])[/B] method, which can transform a number written like a string into a decimal number.

But, still, if the variable has the value "xyz", [B]parseInt()[/B] will return a NaN (Not A Number). That is a paradoxically property, as the type pf the variable is a number, indeed, but is a number which has the property NaN, that means a number which is not a number ? Sounds silly, but this is how it works.

You may also change an array into a string, using the array's method join()

<i>
 </i>var stringArray=(['a','b','c'].join())
 alert(typeof(stringArray)) // returns a String type of

Or, you may parse a decimal integer into a number of another base (which has the type of = String) using[B] toString([/B][I]base[/I][B])[/B]

<i>
 </i>var numberHexa=(255).toString(16);
 alert(numberHexa); // returns "ff", the hexa equivaluent of the decimal 255
 alert(typeof(numberHexa)) // returns String

There are also methods to transform a String into a JSON Object, but only if the string is written following a certain JSON syntax.

Well, you may consider those methods to be able to change the type of a variable, but there are a lot of restrictive conditions which those variables have to comply before being "transformed". In fact those methods transform those variables into [I]something else[/I]. The new type is a[I] result[/I] of that transformation, not a [I]scope[/I] in itself.

how a variable’s type can be changed on-the-fly.

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