Equivalent of PHP’s in_array() function

Posted on September 13, 2008, under JavaScript 

Hello coders,

This is a JavaScript function that works like in_array() in PHP. Below is the function with a usage example:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
 <HEAD>
  <TITLE>Equivalent of PHP in_array() | JavaScript Library</TITLE>
  <META NAME="Author" CONTENT="Bit Repository">

  <META NAME="Keywords" CONTENT="in_array, php, javascript">
  <META NAME="Description" CONTENT="Equivalent of PHP in_array() | JavaScript Library">

<SCRIPT LANGUAGE="JavaScript">

function in_array(string, array)
{
   for (i = 0; i < array.length; i++)
   {
      if(array[i] == string)
      {
         return true;
      }
   }
return false;
}

var extensions = new Array("jpg","jpeg","gif","png","bmp");

/*
// Alternative way of creating the array

var extensions = new Array();

extensions[1] = "jpg";
extensions[0] = "jpeg";
extensions[2] = "gif";
extensions[3] = "png";
extensions[4] = "bmp";
*/

var str_to_check = "bmp";

if(in_array(str_to_check, extensions))
{
  alert(str_to_check +" is in our array.");
}
else
{
  alert(str_to_check +" is not in our array.");
}


</SCRIPT>

</HEAD>
<BODY>
</BODY>
</HTML>

If you have any comments or suggestions regarding this script please post them.

  • September 13, 2008
  • article by Gabriel C.
  • 6 comments

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6 Replies to "Equivalent of PHP’s in_array() function"

  1. z
    September 13, 2008 at 5:44 AM
    Reply

    More concise:
    function in_array(string, array) {
    for(var i=0; i<array.length; i++) {
    if (array[i] == string) return true;
    }
    return false;
    }

  2. Tim
    September 25, 2008 at 4:13 AM
    Reply

    Even better:

    Array.prototype.in_array = function(str){
    for(var i=0; i<this.length; i++)
    if (this[i] == str)
    return true;
    return false
    }

  3. John Boyd
    August 31, 2009 at 2:07 PM
    Reply

    Hey quick question. How the heck do you get javascript to work when there is a field name like: name=”state[]” due to php requirement for the check boxes??

  4. Pastel.pro
    January 18, 2010 at 7:59 PM
    Reply

    Even more concise (Array.prototype.in_array adds the fonction string in the array !) :

    function in_array (string, array) {
    for (i in array) if(array[i] == string) return true;
    return false;
    };

  5. Darren
    April 1, 2010 at 5:22 AM
    Reply

    Thank you for this code it helped out a lot.

    In regards to John the POST variable automatically converts to a PHP array so that is how you do it. You loop through the PHP array equivalent.

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