Here are 2 prototype-functions I created.

[tilspam@ofir.dk]

Timing for optimization purposes:

Function.prototype.time =
  function() {
    var sTime = new Date();
    this.apply(null,arguments);
    var eTime = new Date();
    return eTime.getTime() - sTime.getTime();
  };

Say you have a function f. To time the function with arguments arg0, arg1 & arg2 do

f.time(arg0,arg1,arg2);

[tilspam@ofir.dk]

To remove an element from an array and shrink it

Array.prototype.removeElement = 
  function(obj) {
    for (var i=0;i<this.length;i++) {
      if (this[i] == obj) {
        this[i] = this[this.length-1];
        this.pop();
        break;
      }
    }
  };

Only use this if the order of the elements in the array is not important

[scragar]

To remove an element from an array and shrink it

Array.prototype.removeElement = 
  function(obj) {
    for (var i=0;i<this.length;i++) {
      if (this[i] == obj) {
        this[i] = this[this.length-1];
        this.pop();
        break;
      }
    }
  };

Only use this if the order of the elements in the array is not important

If the order is important then what's wrong with this small set of changes?

Array.prototype.removeElement = function(){
  var found = false;
  for (var i=0; i<this.length; i++) {
    if (this[i] == arguments[0]) {
      found = true;
    }
    if(found && this.length-1 != i){
     this[i] = this[i+1];
    };
  };
  this.pop();
}; 

[tilspam@ofir.dk]

If the order is important then what's wrong with this small set of changes

Probably nothing ... but this is faster

Array.prototype.removeElement =
  function() { 
    for (var i=0; i<this.length; i++) { 
      if (this[i] == arguments[0]) {
        for (var j=i;j<this.length-1;j++)
          this[j] = this[j+1];
        this.pop();
        break;
      }
    }
  };

[BigMoosie]

This is not as fast but more useful, it can take 2 arguments, the first is the same as yours (the value to be removed) however the second defines how many of it to remove, if the second is not sent then it will simply remove them all:

Array.prototype.removeElement=function() { 
	var arrayLength=this.length;
	var count=0;
	var limit=arguments[1];
	if (limit==null) limit=arrayLength;
	for (var i=0; i<arrayLength; i++){
		if (this[i]==arguments[0] && count<limit) count++;
		else this[i-count]=this[i];	
	}
	this.splice(this.length-count, this.length);
	return count;
};

[tilspam@ofir.dk]

BigMoosie> Instead of pop'ing count times use slice. Replace your 2nd for loop with

this = this.slice(0,count);

[BigMoosie]

Timing for optimization purposes:

Function.prototype.time =
  function() {
    var sTime = new Date();
    this.apply(null,arguments);
    var eTime = new Date();
    return eTime.getTime() - sTime.getTime();
  };

Say you have a function f. To time the function with arguments arg0, arg1 & arg2 do

f.time(arg0,arg1,arg2);

You only need to use eTime-sTime.

There are two ways of measuring the speed of these Array prototypes, the wrong way is to do it a few thousand times on a short array, make sure that you are timing it once on a huge (or as ultimater always says: hugh) array (I dont doubt that you already know this, but just for others).

[tilspam@ofir.dk]

or even better use Array.splice()

this.splice(this.length-count);

[BigMoosie]

Thanx for that I made the fix (the first one didnt work because you cannot directly change this), but do note that splice requires a second argument (where to stop cutting). I also made it return count.

[tilspam@ofir.dk]

...but do note that splice requires a second argument (where to stop cutting)...

No. Second argument is optional. If not supplied splice will delete all elements from the value of the first argument untill the end of the array.

var arr1 = new Array(1,2,3,4,5,6,7);
var arr2 = new Array();
arr2 = arr1.splice(4);

// arr1 is now [1,2,3,4] and arr2 is [5,6,7]

[BigMoosie]

Not in Internet Explorer it isnt.

[tilspam@ofir.dk]

Your right...but according to JS The Definitive Guide the behaviour should be as in my last post. Guess its a bug in IE then...

[Ultimater]

String.prototype.pack is a function that packs the given string to the given amount of characters. If a string is 3 characters long and you pack(10) it then the string becomes 7 spaces longer. If you pack(10) a string of 50 characters, it is cut to only the first 10 characters. So either way your packing the string to 10 characters with pack(10).

<script type="text/javascript">
String.prototype.multipulCopies=function(){var temp="";for(var i=0;i<arguments[0];i++){temp+=this}return temp}
String.prototype.pack=function(){var tempS=this.substr(0,arguments[0]);var tempL=arguments[0]-this.length;var spaces=" ".multipulCopies(tempL);return tempS+spaces}
alert("this message is too big!".pack(5))
alert("a".pack(10)+"b")
</script>

The pack function uses the multipulCopies function when it is defined.

[A1ien51]

I use this:

<script>
 Date.prototype.NumberOfDays =
  function(){ 
    this.setDate(1); //set date to first avoids problem with 31/30 day months!
    this.setMonth(this.getMonth()+1);
    this.setDate(0);
    return this.getDate();
  }

  var today = new Date()
  alert(today.NumberOfDays())
</script>

Eric

[Ultimater]

Woah! That one is very useful! Thanks Eric!
That is a great way to find the number of days in each month.