number is calculated from the whole parameter to the number type
Alert (Number (")");//0
//alert (number ([]));//0
Alert (number (' 20 yuan ')); =>nan
Alert (number (null));=>0;
Alert (number (document));=>nan;
Alert (number (NaN));=>nan;
Alert (number (true));=>1;
Alert (number (undefined));=>nan;
parsefloat and the parseint the related operations are from left to right in order!
For example : Alert (parsefloat (' abc '));//nan
//alert (parsefloat (' 20 Yuan '));//20
Alert (parsefloat ([]));//nan
//alert (parsefloat (' 20.78 yuan '));//20.78
//alert (parsefloat (' 200px ' -30));//nan
//alert (parsefloat () (function () {alert (1);}); /nan
//alert (parsefloat (document));//nan
//alert (parsefloat (true));
Alert (parsefloat (null));//nan
//alert (typeof NaN);//number
//alert (parsefloat (' SBC '));
//alert (typeof (' abc '-6));
//alert (parsefloat (' xyz ' -90));//nan
Alert (parsefloat (NaN));//nan involved in any of the relevant operations = = nan!
This article is from "Spring!" "blog, declined reprint!"
JavaScript: Fourth number and parsefloat and parseint Order of operations Note!