JS中的数学计算<之简单实例讲解>

var a=10%3;

//a=1

var a=Math.abs(-102.1);
var b=Math.abs(102.1);

//a=102.1;b=102.1

var num_1 = new Number(13.53);
alert(num_1.toFixed(1));
alert(num_1.toFixed(0));

//13.5
//14

var num_2 = new Number(13.56);
alert(num_2.toFixed(1));
alert(num_2.toFixed(0));

//13.6
//14

Math.min(5,7) 
Math.min(-3,5) 
Math.min(-3,-5) 
(Math.min(7.25,7.30)

//结果
//5
//-3
//-5
//7.25

Math.max(5,7,9) 
Math.max(-3,5) 
Math.max(-3,-5) 
Math.max(7.25,7.30)

//结果
//9
//5
//-3
//7.30

var a=1000.25;
alert(a.toPrecision(1))
alert(a.toPrecision(2))
alert(a.toPrecision(4))
alert(a.toPrecision(6))
alert(a.toPrecision(8))

//结果
//1e+3
//1.0e+3
//1000
//1000.25
//1000.2500

Math.round(0.60) 
Math.round(0.50) 
Math.round(0.49)
Math.round(-4.40) 
Math.round(-4.60)

//结果
//1
//1
//0
//-4
//-5