JavaScript four arithmetic operations
Author：Eve Cole
Update Time：2009-06-11 16:23:19
<script type="text/javascript">
var alsoAString = '25';
var isANumber = 25;
// var isEqual = (alsoAString==isANumber); // This is true, they are both 25.
var isEqual = (alsoAString===isANumber); // False , one is a number, the other a string.
// alert(isEqual);
var floatError=0.06+0.01
//alert(floatError);
//Division function, used to get accurate division results
//Note: The division result of JavaScript will have errors, which will be more obvious when dividing two floating point numbers. This function returns a more accurate division result.
//Call: accDiv(arg1,arg2)
//Return value: the exact result of dividing arg1 by arg2
function accDiv(arg1,arg2){
var t1=0,t2=0,r1,r2;
try{t1=arg1.toString().split(".")[1].length}catch(e){}
try{t2=arg2.toString().split(".")[1].length}catch(e){}
with(Math){
r1=Number(arg1.toString().replace(".",""))
r2=Number(arg2.toString().replace(".",""))
return (r1/r2)*pow(10,t2-t1);
}
}
//Add a div method to the Number type to make it more convenient to call.
Number.prototype.div = function (arg){
return accDiv(this, arg);
}
//Multiplication function, used to get accurate multiplication results
//Note: The multiplication result of JavaScript will have errors, which will be more obvious when two floating point numbers are multiplied. This function returns a more accurate multiplication result.
//Call: accMul(arg1,arg2)
//Return value: the exact result of multiplying arg1 by arg2
function accMul(arg1,arg2)
{
var m=0,s1=arg1.toString(),s2=arg2.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)
}
//Add a mul method to the Number type to make it more convenient to call.
Number.prototype.mul = function (arg){
return accMul(arg, this);
}
//Addition function, used to obtain accurate addition results
//Note: The addition result of JavaScript will have errors, which will be more obvious when adding two floating point numbers. This function returns a more accurate addition result.
//Call: accAdd(arg1,arg2)
//Return value: the exact result of arg1 plus arg2
function accAdd(arg1,arg2){
var r1,r2,m;
try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
m=Math.pow(10,Math.max(r1,r2))
return (arg1*m+arg2*m)/m
}
//Add an add method to the Number type to make it more convenient to call.
Number.prototype.add = function (arg){
return accAdd(arg,this);
}
document.writeln("Unimproved operation: 7*0.8="+7*0.8+"<br>");
document.writeln("Operation after improvement: 7*0.8="+(7).mul(0.8)+"<br>");
document.writeln("Unimproved operation: 0.06+0.01=" + 0.06+0.01 +"<br>")
document.writeln("Improved operation: 0.06+0.01=" + 0.06.add(0.01) +"<br>")
</script>
