---
layout: page
title: "JavaScript fread function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/fread:775
- /functions/view/fread
- /functions/view/775
- /functions/fread:775
- /functions/775
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's fread

{% codeblock filesystem/fread.js lang:js https://raw.github.com/kvz/phpjs/master/functions/filesystem/fread.js raw on github %}
function fread (handle, length) {
  // http://kevin.vanzonneveld.net
  // +   original by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: fopen('http://kevin.vanzonneveld.net/pj_test_supportfile_1.htm', 'r');
  // *     example 1: fread(handle, 10);
  // *     returns 1: '123'

  if (!this.php_js || !this.php_js.resourceData || !this.php_js.resourceDataPointer) {
    return false;
  }

  length = length < 8192 ? (Math.floor(length / 2) || 1) : 4096; // 2 bytes per character (or surrogate) means limit of 8192 bytes = 4096 characters; ensure at least one

  var start = this.php_js.resourceDataPointer[handle.id];

  if (start === undefined) {
    return false; // Resource was already closed
  }

  if (!this.php_js.resourceData[handle.id][start]) {
    return ''; // already reached the end of the file (but pointer not closed)
  }

  this.php_js.resourceDataPointer[handle.id] += length;

  return this.php_js.resourceData[handle.id].substr(start, length); // Extra length won't be a problem here
}
{% endcodeblock %}

 - [view on github](https://github.com/kvz/phpjs/blob/master/functions/filesystem/fread.js)
 - [edit on github](https://github.com/kvz/phpjs/edit/master/functions/filesystem/fread.js)

### Example 1
This code
{% codeblock lang:js example %}
fopen('http://kevin.vanzonneveld.net/pj_test_supportfile_1.htm', 'r');
fread(handle, 10);
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
'123'
{% endcodeblock %}


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