Javascriptの型変換

型変換の関数も用意されていますが
こんなんでも出来るんですね

var myVar   = "3.14159",
str   = ""+ myVar,//  to string
int   = ~~myVar,  //  to integer
float = 1*myVar,  //  to float
bool  = !!myVar,  /*  to boolean - any string with length and any number except 0 are true */
array = [myVar];  //  to array

http://www.ideaxidea.com/archives/2010/03/javascript_type_conversion.html