Archive for the ‘indexOf’ Tag

IE7 and IE8’s indexOf() Array Bug

If you try to use indexOf() to check the existence of an Array member in <IE9 the script will fail. This is because the Array class in <IE9 does not have the function indexOf() built into it. This is not amazing.

To render this problem obsolete you could use the jQuery inArray() method, although then you are dependent on jQuery being in existence – http://api.jquery.com/jquery.inarray/

Or, alternatively you could just add indexOf onto the Array prototype if it doesn’t exist using something like this:-

// <IE9 indexOf() fix
if (!Array.indexOf) {
  Array.prototype.indexOf = function (obj, start) {
    for (var i = (start || 0); i < this.length; i++) {
      if (this[i] == obj) {
        return i;
       }
    }
   return -1;
  }
}

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