?come from http://www.cnblogs.com/konooo/archive/2010/01/23/1654617.html

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1. //浮点数加法运算??
2. ?function?FloatAdd(arg1,arg2){??
3. ???var?r1,r2,m;??
4. ???try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}??
5. ???try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}??
6. ???m=Math.pow(10,Math.max(r1,r2))??
7. ???return?(arg1*m+arg2*m)/m??
8. ??}??
9. ??
10. ?//浮点数减法运算??
11. ?function?FloatSub(arg1,arg2){??
12. ?var?r1,r2,m,n;??
13. ?try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}??
14. ?try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}??
15. ?m=Math.pow(10,Math.max(r1,r2));??
16. ?//动态控制精度长度??
17. ?n=(r1>=r2)?r1:r2;??
18. ?return?((arg1*m-arg2*m)/m).toFixed(n);??
19. ?}??
20. ???
21. ?//浮点数乘法运算??
22. ?function?FloatMul(arg1,arg2)???
23. ?{???
24. ??var?m=0,s1=arg1.toString(),s2=arg2.toString();???
25. ??try{m+=s1.split(".")[1].length}catch(e){}???
26. ??try{m+=s2.split(".")[1].length}catch(e){}???
27. ??return?Number(s1.replace(".",""))*Number(s2.replace(".",""))/Math.pow(10,m)???
28. ??}???
29. ??
30. ??
31. //浮点数除法运算??
32. function?FloatDiv(arg1,arg2){???
33. var?t1=0,t2=0,r1,r2;???
34. try{t1=arg1.toString().split(".")[1].length}catch(e){}???
35. try{t2=arg2.toString().split(".")[1].length}catch(e){}???
36. with(Math){???
37. r1=Number(arg1.toString().replace(".",""))???
38. r2=Number(arg2.toString().replace(".",""))???
39. return?(r1/r2)*pow(10,t2-t1);???
40. }???
41. }??