# JS數據類型轉換 ## 一：示例 |例 句 | 結 果| | --- | --- | |parseInt('1234') | 1234| |parseInt('1234.00') | 1234| |parseInt('1234abc') | 1234| |parseInt('abc1234') | undefined(轉換失敗)| |parseFloat('1234.123') | 1234.123| |parseFloat('1234.123a') | 1234.123| |parseFloat('a1234.123') | NaN| |Number('1234.123') | 1234.123| |Number('1234.123aa') | NaN| |String(eval('12+10')) | 22 |Boolean('0'),Boolean('567'),Boolean(567) | true| |Boolean(null),Boolean(false),Boolean(0),Boolean(''),Boolean() false| |this.toString() | [object]| |(typeof(this)).toString() object| |eval('12+34') | 46| |eval('12+34')+'' | 46| |eval('12+34')*1.0 | 46| |typeof(eval('12+34')*1.0) | number| |typeof(eval('12+34')+'') | string| ## 二：知識 TODO