I'm having several div's #mydiv1, #mydiv2, #mydiv3, ... and want to assign click handlers to them:
$(document).ready(function(){
for(var i = 0; i < 20; i++) {
$('#question' + i).click( function(){
alert('you clicked ' + i);
});
}
});
But instead of showing 'you clicked 3' when click on #mydiv3 (as for every other click) I get 'you clicked 20'. What am I doing wrong?
在Javascript中创建closures in loops是一个常见的错误.你需要有这样的回调函数:
function createCallback( i ){
return function(){
alert('you clicked' + i);
}
}
$(document).ready(function(){
for(var i = 0; i < 20; i++) {
$('#question' + i).click( createCallback( i ) );
}
});
Update June 3, 2016: since this question is still getting some traction and ES6 is getting popular as well, I would suggest a modern solution. If you write ES6, you can use the let keyword, which makes the i variable local to the loop instead of global:
for(let i = 0; i < 20; i++) {
$('#question' + i).click( function(){
alert('you clicked ' + i);
});
}
It's shorter and easier to understand.