Conversion function, forced type conversion, weak type conversion using js variables.

Use the functions parseInt () and parseFloat () to convert values to integers and the latter to floating-point numbers. Only by calling these methods on a numeric String of type String can these two functions run correctly; For other types, NaN (non-numeric) is returned.

parse int(" 1234 blue ")； ? //Results? 1234

parse int(" 0xA ")； ? //Results? 10

parse int(" 22.5 ")； ? //Results? 22

parse int(" blue ")； ? //Results? Disc scone

parse float(" 1234 blue ")； ? //Results? 1234.0

parse float(" 0xA ")； ? //Results? Disc scone

parse float(" 22.5 ")； ? //Results? 22.5

parse float(" 22 . 34 . 5 ")； ? //Results? 22.342. Forced type conversion, number(value)- converts a given value into a number (which can be an integer or a floating-point number);

Number (fake)? //Results? 0

Numbers (true)? //Results? 1

Quantity (undefined)? //Results? Disc scone

Number (empty)? //Results? 0

No. (? "5.5?" )? //Results? 5.5

No. (? "56?" )? //Results? Fifty-six

No. (? "5.6.7?" )? //Results? Disc scone

No. (new? Object())？ //Results? Disc scone

No (100)? //Results? 1003. Using js variables for weak type conversion

var？ str=？ '0 12.345?' ;

var？ x？ =? str-0；

x？ =? x * 1； ? //x performs arithmetic operation on the number type to realize the type conversion from string to number, but this method is not recommended.