javascript如何判断一个数字是否是另一个数字的倍数

问题描述：

我正在为一家面料商店建造一个计算量很大的购物车，并且发现自己需要对用户输入的长度*每米的基本价格进行计算，然后检查结果以查看它是否为图案长度。如果它不是倍数，我需要找到模式长度的最接近的倍数并将结果更改为。

I'm building a fairly calculation-heavy cart for a fabric store and have found myself needing to do a calculation on user inputted length * the baseprice per metre, but then checking the result to see if it is a multiple of the pattern length. If it is not a multiple, I need to find the closest multiple of the pattern length and change the result to that.

我还需要能够完全执行PHP中的相同计算，但是如果有人可以帮我解决数学问题，我可以移植任何需要自己翻译的东西。

I need to also be able to do exactly the same calculation in PHP, but if anyone can help me out with the maths I can port anything that needs to be translated myself.

我正在使用jQuery 1.6.2并已经完成计算的第一部分，我只需要根据模式长度检查（米*价格）的结果。

I am using jQuery 1.6.2 and already have the first part of the calculation done, I just need to check the result of (metres*price) against the pattern length.

任何帮助非常感谢

编辑：这些计算都涉及价格和模式长度的2位小数。用户输入的长度也可能包含小数。

These calculations all involve 2 decimal places for both the price and the pattern length. User inputted length may also contain decimals.

答

使用％（ Javascript和PHP中的模数运算符，当 a 在 b 时返回余数> a％b 。当 a 是 b 的倍数时，余数将为零。

Use the % (modulus) operator in Javascript and PHP, which returns the remainder when a is divided by b in a % b. The remainder will be zero when a is a multiple of b.

前。

//Javascript
var result = userLength * basePrice;     //Get result
if(result % patternLength){              //Check if there is a remainder
  var remainder = result % patternLength; //Get remainder
  if(remainder >= patternLength / 2)      //If the remainder is larger than half of patternLength, then go up to the next mulitple
    result += patternLength - remainder;
  else                                    //Else - subtract the remainder to go down
    result -= remainder;
}
result = Math.round(result * 100) / 100;  //Round to 2 decimal places

javascript如何判断一个数字是否是另一个数字的倍数

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