 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 
<html> 
<head> 
<title>floatDecimal.html</title> 
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 
<meta http-equiv="description" content="this is my page"> 
<meta http-equiv="content-type" content="text/html; charset=gb2312"> 
<script type="text/javascript"> 
//保留兩位小數(shù) 
//功能：將浮點(diǎn)數(shù)四舍五入，取小數(shù)點(diǎn)后2位 
function toDecimal(x) { 
var f = parseFloat(x); 
if (isNaN(f)) { 
return; 
} 
f = Math.round(x*100)/100; 
return f; 
} 
//制保留2位小數(shù)，如：2，會(huì)在2后面補(bǔ)上00.即2.00 
function toDecimal2(x) { 
var f = parseFloat(x); 
if (isNaN(f)) { 
return false; 
} 
var f = Math.round(x*100)/100; 
var s = f.toString(); 
var rs = s.indexOf('.'); 
if (rs < 0) { 
rs = s.length; 
s += '.'; 
} 
while (s.length <= rs + 2) { 
s += '0'; 
} 
return s; 
} 
function fomatFloat(src,pos){ 
return Math.round(src*Math.pow(10, pos))/Math.pow(10, pos); 
} 
//四舍五入 
document.writeln("保留2位小數(shù)：" + toDecimal(3.14159267) + '<br/>'); 
document.writeln("強(qiáng)制保留2位小數(shù)：" + toDecimal2(3.14159267) + '<br/>'); 
document.writeln("保留2位小數(shù)：" + toDecimal(3.14559267) + '<br/>'); 
document.writeln("強(qiáng)制保留2位小數(shù)：" + toDecimal2(3.15159267) + '<br/>'); 
document.writeln("保留2位小數(shù)：" + fomatFloat(3.14559267, 2) + '<br/>'); 
document.writeln("保留1位小數(shù)：" + fomatFloat(3.15159267, 1) + '<br/>'); 
//五舍六入 
document.writeln("保留2位小數(shù)：" + 1000.003.toFixed(2) + '<br/>'); 
document.writeln("保留1位小數(shù)：" + 1000.08.toFixed(1) + '<br/>'); 
document.writeln("保留1位小數(shù)：" + 1000.04.toFixed(1) + '<br/>'); 
document.writeln("保留1位小數(shù)：" + 1000.05.toFixed(1) + '<br/>'); 
//科學(xué)計(jì)數(shù) 
document.writeln(3.1415.toExponential(2) + '<br/>'); 
document.writeln(3.1455.toExponential(2) + '<br/>'); 
document.writeln(3.1445.toExponential(2) + '<br/>'); 
document.writeln(3.1465.toExponential(2) + '<br/>'); 
document.writeln(3.1665.toExponential(1) + '<br/>'); 
//精確到n位，不含n位 
document.writeln("精確到小數(shù)點(diǎn)第2位" + 3.1415.toPrecision(2) + '<br/>'); 
document.writeln("精確到小數(shù)點(diǎn)第3位" + 3.1465.toPrecision(3) + '<br/>'); 
document.writeln("精確到小數(shù)點(diǎn)第2位" + 3.1415.toPrecision(2) + '<br/>'); 
document.writeln("精確到小數(shù)點(diǎn)第2位" + 3.1455.toPrecision(2) + '<br/>'); 
document.writeln("精確到小數(shù)點(diǎn)第5位" + 3.141592679287.toPrecision(5) + '<br/>'); 
</script> 
</head> 
<body> 
This is my HTML page. <br> 
</body> 
</html> 

javascript四舍五入保留兩位小數(shù)

復(fù)制代碼代碼如下:

function count(){
   //alert("count");
   var size=~~(document.getElementById("size").value);
   var value=0;
   for(var i=0;i<size;i++){
    var val=1*(document.getElementById("afterAdjScor"+i).value);
    if(null!=val){
     value =Math.round((1*(value+val))*100)/100;
    }
   }
   if(isNaN(value)){
    value="輸入必須為數(shù)字類型";
   }
   document.getElementById("total").value=value;
  }

說(shuō)明:~~XX:字符串轉(zhuǎn)int
1*XX:字符串轉(zhuǎn)float
Math.round((1*(value+val))*100)/100:四舍五入

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