* 一、转化为数字*/

console.log(‘123123’*1.0);

/* 二、从一个值中提取另一中类型的值，并完成转化工作 */

console.log(parseInt(‘1233zxhag’)); //1233

console.log(parseFloat(‘1.123aef’)); //1.123

console.log(eval(1+123)); //124

console.log(toString(123)); //[object Window] ‘123’

/* 将整个值从一种类型转化成另一种类型(称作基本类型转换) */

console.log(String(‘123123′));

console.log(String(null)); //null

console.log(String(undefined)); //undefined

console.log(Number(‘123123′));

console.log(Number(null)); // 0

console.log(Number(undefined)); //NaN

console.log(Boolean(123123)); //true

console.log(Boolean(null)); //false

console.log(Boolean(undefined)); //false

本文转自（http://dayney.com/?p=38)