---
layout: page
title: "JavaScript fmod function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/fmod:404
- /functions/view/fmod
- /functions/view/404
- /functions/fmod:404
- /functions/404
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's fmod

{% codeblock math/fmod.js lang:js https://raw.github.com/kvz/phpjs/master/functions/math/fmod.js raw on github %}
function fmod (x, y) {
  // From: http://phpjs.org/functions
  // +   original by: Onno Marsman
  // +      input by: Brett Zamir (http://brett-zamir.me)
  // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // *     example 1: fmod(5.7, 1.3);
  // *     returns 1: 0.5
  var tmp, tmp2, p = 0,
    pY = 0,
    l = 0.0,
    l2 = 0.0;

  tmp = x.toExponential().match(/^.\.?(.*)e(.+)$/);
  p = parseInt(tmp[2], 10) - (tmp[1] + '').length;
  tmp = y.toExponential().match(/^.\.?(.*)e(.+)$/);
  pY = parseInt(tmp[2], 10) - (tmp[1] + '').length;

  if (pY > p) {
    p = pY;
  }

  tmp2 = (x % y);

  if (p < -100 || p > 20) {
    // toFixed will give an out of bound error so we fix it like this:
    l = Math.round(Math.log(tmp2) / Math.log(10));
    l2 = Math.pow(10, l);

    return (tmp2 / l2).toFixed(l - p) * l2;
  } else {
    return parseFloat(tmp2.toFixed(-p));
  }
}
{% endcodeblock %}

 - [Raw function on GitHub](https://github.com/kvz/phpjs/blob/master/functions/math/fmod.js)

Please note that php.js uses JavaScript objects as substitutes for PHP arrays, they are 
the closest match to this hashtable-like data structure. 

Please also note that php.js offers community built functions and goes by the 
[McDonald's Theory](https://medium.com/what-i-learned-building/9216e1c9da7d). We'll put online 
functions that are far from perfect, in the hopes to spark better contributions. 
Do you have one? Then please just: 

 - [Edit on GitHub](https://github.com/kvz/phpjs/edit/master/functions/math/fmod.js)

### Example 1
This code
{% codeblock lang:js example %}
fmod(5.7, 1.3);
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
0.5
{% endcodeblock %}


### Other PHP functions in the math extension
{% render_partial _includes/custom/math.html %}