全局变量更新不触发jQuery中的if / else语句

Question

See the example below, basically I want it to execute if on the first click, and then for all subsequent clicks to execute the else statement but even though the variable is updating it isn't switching to else eg if the alert message is saying the variable is now at three it still doesn't go to else. I'm guessing it's a scope issue but how do I get around it - can anyone advise?

var loaded = 0;

if (loaded == 0) {
$('body').on('click', '#button', function(){
alert(loaded);
loaded += 1;
});

} else {
alert(loaded + 'yay its not 0');
};

Answer 1

This should hopefully behave as intended:

$(document).ready(function() {
    var clicked = false;
    $('body').click(function() { 
        if(clicked) {
            alert("Already clicked");
        } else {
            alert("Not clicked yet");
            clicked = true;
        }
    });
});

Hope that helped.

Answer 2

Your if condition only runs one time. Try placing your check within the click event:

var loaded = 0;
$('body').on('click', '#button', function () {
    if (loaded == 0) {
        alert(loaded);
        loaded += 1;
    } else {
        alert(loaded + 'yay its not 0');
    };
});

jsFiddle example

Answer 3

Events dont work like that once its assigned it always runs unless you use .one or manually call .off after the fact - but even then your check will only get executed once when the script loads, not when a click happens. You need to handle the if/else inside your event handler.

var loaded = 0;
$('body').on('click', '#button', function(){
   if(loaded === 0) {
      alert(loaded);
      loaded += 1;
   } else {

   }
});

Answer 4

Put your check inside the click handler:

  $('body').on('click', '#button', function(){
      if(loaded == 0){
          alert(loaded);
          loaded += 1;
      }
      else{
         alert(loaded + 'yay its not 0');

      }
   });

Answer 5

The if statement is only executed the first time, after that you enter the on() method and bind the function to #button , but there's no other evaluation afterwards, in this case it'd only go to the else part if loaded 's initial value wasn't 0, so you should change your code to:

$('body').on('click', '#button', function(){
if (loaded == 0) {
  alert(loaded);
loaded += 1;
  } else {
alert(loaded + 'yay its not 0');
  }
});