Refactor javascript into loop

Question

How can I put the following into a loop:

 if ($('#s1').attr('checked') ){
 image(s1, mouseX-s1.width/2+random(-brushSize, brushSize), mouseY-s1.height/2+random(-brushSize, brushSize));
 }
 if ($('#s2').attr('checked') ){
 image(s2, mouseX-s2.width/2+random(-brushSize, brushSize), mouseY-s2.height/2+random(-brushSize, brushSize));
 }
 if ($('#s3').attr('checked') ){
 image(s3, mouseX-s3.width/2+random(-brushSize, brushSize), mouseY-s3.height/2+random(-brushSize, brushSize));
 }
 if ($('#s4').attr('checked') ){
 image(s4, mouseX-s4.width/2+random(-brushSize, brushSize), mouseY-s4.height/2+random(-brushSize, brushSize));
 }
 if ($('#s5').attr('checked') ){
 image(s5, mouseX-s5.width/2+random(-brushSize, brushSize), mouseY-s5.height/2+random(-brushSize, brushSize));
 }

Thanks

• jerluc: Can you provide anymore code relating to the image() function or the s1,...,s5 variables?
• tekknolagi: i would make an array for #s instead of variables -> easier to keep track of and smoother
• tekknolagi: then i would use the switch() statement to go through the array
• Rigil: image() is part of processing.js s1-s5 are just setting the image eg s1 = loadImage("images/stars/1.png")
• Phrogz: It would be better if s1-s5 were not local variables, but either items in an array or properties of an object.

Answer 1

I think the simplest is to create a special class for every element you want to access (and keep the incremental id) and use the .each() function from jquery.

So you do something like

$('.yourClass:checked').each(function(index) {
 var my_id = $(this).attr(id); // or use the index
 image(my_id, mouseX-s5.width/2+random(-brushSize, brushSize), mouseY-s5.height/2+random(-brushSize, brushSize));
 });

• Simon marc: Sorry I but my_id into the image funtion, but use the id to get the data from array, or whatever you have.

Answer 2

One example that directly translates your series of ifs into a loop:

var sElements = [ s1, s2, s3, s4, s5 ]; // Declare an array so that you can reference the s1..5 variables using a numeric index stored in a variable
for (var i = 0; i < sElements.length; i++) { // Plain old loop, nothing remotely fancy
 if ($('#s' + (i + 1)).attr('checked')) { // Note the string concatenation with the number (i + 1)
 var s = sElements[i]; // Put the ith element into a variable for easier referencing
 image(s, mouseX - s.width/2 + random(-brushSize, brushSize), mouseY - s.height/2 + random(-brushSize, brushSize));
 }
}

Note that you should probably use more meaningful variable names -- this will increase the readability and maintainability of your code.

Answer 3

You should attach the image() function as a callback for each object individually.

$("#id").click(){function() {
 image();
});