js处理浮点数问题

// 两个浮点数求和
function accAdd(num1,num2){
var r1,r2,m;
try{
r1 = num1.toString().split('.')[1].length;
}catch(e){
r1 = 0;
}
try{
r2=num2.toString().split(".")[1].length;
}catch(e){
r2=0;
}
m=Math.pow(10,Math.max(r1,r2));
// return (num1*m+num2*m)/m;
return Math.round(num1*m+num2*m)/m;
}

// 两个浮点数相减
function accSub(num1,num2){
var r1,r2,m;
try{
r1 = num1.toString().split('.')[1].length;
}catch(e){
r1 = 0;
}
try{
r2=num2.toString().split(".")[1].length;
}catch(e){
r2=0;
}
m=Math.pow(10,Math.max(r1,r2));
n=(r1>=r2)?r1:r2;
return (Math.round(num1*m-num2*m)/m).toFixed(n);
}
// 两数相除
function accDiv(num1,num2){
var t1,t2,r1,r2;
try{
t1 = num1.toString().split('.')[1].length;
}catch(e){
t1 = 0;
}
try{
t2=num2.toString().split(".")[1].length;
}catch(e){
t2=0;
}
r1=Number(num1.toString().replace(".",""));
r2=Number(num2.toString().replace(".",""));
return (r1/r2)*Math.pow(10,t2-t1);
}

function accMul(num1,num2){
var m=0,s1=num1.toString(),s2=num2.toString();
try{m+=s1.split(".")[1].length}catch(e){};
try{m+=s2.split(".")[1].length}catch(e){};
return Number(s1.replace(".",""))*Number(s2.replace(".",""))/Math.pow(10,m);
}

document.write("使用js原生态方法");
document.write("<br/> 1.01 + 1.02 ="+(1.01 + 1.02));
document.write("<br/> 1.01 - 1.02 ="+(1.01 - 1.02));
document.write("<br/> 0.000001 / 0.0001 ="+(0.000001 / 0.0001));
document.write("<br/> 0.012345 * 0.000001 ="+(0.012345 * 0.000001));
document.write("<br/><hr/>");
document.write("<br/>使用自定义方法");
document.write("<br/> 1.01 + 1.02 ="+accAdd(1.01,1.02));
document.write("<br/> 1.01 - 1.02 ="+accSub(1.01,1.02));
document.write("<br/> 0.000001 / 0.0001 ="+accDiv(0.000001,0.0001));
document.write("<br/> 0.012345 * 0.000001 ="+accMul(0.012345,0.000001));