js 四捨五入 保留自訂位元小數 的 函數

function round(v,e)<br /> {<br /> var t=1;<br /> for(;e>0;t*=10,e--);<br /> for(;e<0;t/=10,e++);<br /> return Math.round(v*t)/t;<br /> } </p><p> function FormatNumber(srcStr,nAfterDot){<br /> var srcStr,nAfterDot;<br /> var resultStr,nTen;<br /> srcStr = ""+srcStr+"";<br /> strLen = srcStr.length;<br /> dotPos = srcStr.indexOf(".",0);<br /> if (dotPos == -1){<br /> resultStr = srcStr+".";<br /> for (i=0;i<nAfterDot;i++){<br /> resultStr = resultStr+"0";<br /> }<br /> }<br /> else{<br /> if ((strLen - dotPos - 1) >= nAfterDot){<br /> nAfter = dotPos + nAfterDot + 1;<br /> nTen =1;<br /> for(j=0;j<nAfterDot;j++){<br /> nTen = nTen*10;<br /> }<br /> resultStr = Math.round(parseFloat(srcStr)*nTen)/nTen;<br /> }<br /> else{<br /> resultStr = srcStr;<br /> for (i=0;i<(nAfterDot - strLen + dotPos + 1);i++){<br /> resultStr = resultStr+"0";<br /> }</p><p> }<br /> }</p><p> return resultStr;</p><p>}