TW Blog :: Archives for August 2004

Array Prototyping for Legacy Support

Relates to DOM Scripting and Exploder

This is a reminder to self (since this trap keeps stinging me!) that IE 5.01 does not support the principle Array object methods in Javascript. A way around this problem is to test for the presence of these methods in the Array prototype property and if they do not exist define them. Here are examples for Array.push and Array.splice which I find myself using regularly in DOM based scripts.

if (typeof Array.prototype.push == "undefined") {
  Array.prototype.push = function(str) {
    this[this.length] = str;
  }
}

if (typeof Array.prototype.splice == "undefined") {
  Array.prototype.splice = function(offset, length) {
    var temp = [];
    for (var i = this.length - 1; i >= 0; i–) {
      if (i < offset || i > (offset + length - 1)) {
        temp[temp.length] = this[i];
      }
      this.length–;
    }
    for (i = temp.length - 1; i >= 0; i–) {
      this[this.length] = temp[i];
    }
  }
}

Posted on Friday, Aug 13, 2004 at 05:07:03.