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sort() method
- Thread starter Jonnn
- Start date
my_array.sort(simple_sort());
passes the return value of simple_sort to my_array.sort.
my_array.sort(simple_sort); passes the function itself.
--Chessbot
"In that blessed region of Four Dimensions, shall we linger on the threshold of the Fifth, and not enter therein? Ah, no! [...] Then, yielding to our intellectual onset, the gates of the Sixth Dimension shall fly open; after that a Seventh, and then an Eighth -- --" Flatland, A. Square (E. A. Abbott)
passes the return value of simple_sort to my_array.sort.
my_array.sort(simple_sort); passes the function itself.
--Chessbot
"In that blessed region of Four Dimensions, shall we linger on the threshold of the Fifth, and not enter therein? Ah, no! [...] Then, yielding to our intellectual onset, the gates of the Sixth Dimension shall fly open; after that a Seventh, and then an Eighth -- --" Flatland, A. Square (E. A. Abbott)
- Thread starter
- #3
trollacious
Programmer
Without the () you refer to the object itself, not the function of the object.
Lee
Lee
- Thread starter
- #5
Does this behavior only occur when using the sort() method?
...
Where is the sort() method getting the parameters from that are stated in the simple_sort() function???
JavaScript Beginner at work
Code:
simple_sort(item1,item2) {
var result = 0;
if(item1 > item2)
result = 1;
if(item1 < item2)
result = -1;
if(item1 == item2)
result = 0;
return result
}...
Code:
myArr = new Array("Jon","chessbot",cfFlava","trollacious")
myArr.sort(simple_sort)Where is the sort() method getting the parameters from that are stated in the simple_sort() function???
JavaScript Beginner at work
The array.sort method is passing the parameters to the simple_sort function, each time it needs to know how to sort two elements.
What you are doing is passing a reference to the function, so that array.sort knows which function to call (these are commonly called "callback functions"). You can do the same thing yourself. I've written code where I passed the name of a function to a routine. I've even written code where the code dynamically created a function name from a variable and a constant, then checked to see if a function by that name existed, and if so passed it to another function. If you ever have to do that, let me know and I'll tell you how I did it. It took me hours to figure out how to test the generated function name to see if a function by that name existed without generating a "function does not exist" error.
Meddle not in the affairs of dragons,
for you are crunchy, and good with mustard.
What you are doing is passing a reference to the function, so that array.sort knows which function to call (these are commonly called "callback functions"). You can do the same thing yourself. I've written code where I passed the name of a function to a routine. I've even written code where the code dynamically created a function name from a variable and a constant, then checked to see if a function by that name existed, and if so passed it to another function. If you ever have to do that, let me know and I'll tell you how I did it. It took me hours to figure out how to test the generated function name to see if a function by that name existed without generating a "function does not exist" error.
Meddle not in the affairs of dragons,
for you are crunchy, and good with mustard.
- Thread starter
- #7
HeHe, playing with javascript can be very rewarding ...
I always wanted to make one of these. Now my day has come
JavaScript Beginner at work
I always wanted to make one of these. Now my day has come
Code:
<html>
<head>
<title> Typing A Message </title>
<script language="javascript">
var x = 0;
function type_it() {
setInterval("document.getElementById('paragraph').innerHTML = \"<span style='color:red; font-family:verdana; size:26'>\" + document.getElementById('message').innerHTML.substring(0, x++) + \"</span>\"; if(x > document.getElementById('message').value.length){ x=0; }", 150);
}
</script>
<body>
<div align="center">
<h1> <u> On Screen Typer </u> </h1>
</div>
<br/>
<p id="paragraph">
</p>
<br/><br/>
<div align="center">
<form name="form1">
<textarea name="message" cols="50" rows="5" id="message" value="" onclick="this.select()">Change me </textarea>
<br/>
<br/>
<input type="button" value="Type message" onclick="type_it()">
</form>
</div>
</body>
</html>JavaScript Beginner at work
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