Create a Boolean Object
The Boolean object represents two values: "true" or "false".
The following code creates a Boolean object called myBoolean:
var myBoolean=new Boolean();
If the Boolean object has no initial value, or if the passed value is one of the following:
- 0
- -0
- null
- ""
- false
- undefined
- NaN
the object is set to false. For any other value it is set to true (even with the string "false")!
实例:
<!DOCTYPE html> <html> <body> <script> var b1=new Boolean(0); var b2=new Boolean(1); var b3=new Boolean(""); var b4=new Boolean(null); var b5=new Boolean(NaN); var b6=new Boolean("false"); document.write("0 is boolean "+ b1 +"<br>"); document.write("1 is boolean "+ b2 +"<br>"); document.write("An empty string is boolean "+ b3 + "<br>"); document.write("null is boolean "+ b4+ "<br>"); document.write("NaN is boolean "+ b5 +"<br>"); document.write("The string 'false' is boolean "+ b6 +"<br>"); </script> </body> </html>