Number和ParseInt的区别

Number：除了数字、数字型字符串、null、false、""，其它都转换成NaN；

ParseInt：除了数字和带单位的数字，其它都转换成NaN；

		console.log(Number("123"));//123
		console.log(Number(123));//123
        console.log(Number(null));//0
        console.log(Number(false));//0
        console.log(Number(""));//0
        console.log(Number("123px"));//NaN

        console.log(Number("123"));//123
        console.log(parseInt("123px"));//123
        console.log(parseInt(null));//NaN
        console.log(parseInt(false));//NaN
        console.log(parseInt(""));//NaN

Boolean类型的转换规则

1. String：空字符串为false，非空字符串为true

   		console.log(Boolean(""));//false
           console.log(Boolean("1"));//true
   

2. Number：0和NaN为false，非零数值为true

   		console.log(Boolean(0));//false
           console.log(Boolean(NaN));//false
           console.log(Boolean(1));//true
           console.log(Boolean(2));//true
   

3. Object：null为false，不为null为true

   		console.log(Boolean(null));//false
           console.log(Boolean({}));//true
   

4. Undefine：undefin为false

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