你不止一次使用过同一个选择器 [英] You've used the same selector more than once

问题描述

为什么jQuery.lint.js说我多次使用同一个选择器？

Why is jQuery.lint.js saying that I've used the same selector more than once?

这是我的代码：

var seconds = 20;

function updateCountdown() {
    if (seconds === 0) {
        document.forms[0].submit();
    } else {
        $("#countdown").text("Refresh: " + seconds);
        seconds = seconds - 1;
    }
}

jQuery(function($) {
   setInterval("updateCountdown()",1000);
});

它说：

位置：

@ http：// localhost / js / SubmitForm_Countdown .js：7

@ http：//localhost/js/SubmitForm_Countdown.js：13

选择器：＃count

推荐答案

我猜它是指 $（＃countdown）。text（...）。你每秒运行一次相同的选择器。

I would guess it is referring to $("#countdown").text(...). You're running that same selector once every second.

将它缓存在一个变量中并以这种方式引用它会更有效。

It would be more efficient to cache it in a variable, and reference it that way.

var seconds = 20;
var $countdown;   // variable to store #countdown. 
                  // Initialized here so it is in scope of updateCountdown()

function updateCountdown() {
    if (seconds === 0) {
        document.forms[0].submit();
    } else {
           // reference the #countdown element stored in the variable
        $countdown.text("Refresh: " + seconds);
        seconds = seconds - 1;
    }
}

jQuery(function($) {
      // Once document is ready, find the #countdown element, and cache it
   $countdown = $('#countdown');
   setInterval("updateCountdown()",1000);
});

此外，可以认为传递<的命名参考更好/更有效率code> updateCountdown 函数到 setInterval（）而不是字符串。

Also, it could be argued that it is better/more efficient to pass the named reference of the updateCountdown function to the setInterval() instead of a String.

   setInterval(updateCountdown,1000);

---

此外，它看起来并不像你在秒到达 0 时，清除 setInterval（） 。可能是个好主意。

---

Also, it doesn't appear as though you're clearing your setInterval() once seconds reaches 0. Probably a good idea.

var seconds = 20;
var $countdown;   // variable to store #countdown. 
                  // Initialized here so it is in scope of updateCountdown()

var interval; // store reference to the setInterval()

function updateCountdown() {
    if (seconds === 0) {
        document.forms[0].submit();
           // clear the setInterval
        clearInterval( interval );
    } else {
           // reference the #countdown element stored in the variable
        $countdown.text("Refresh: " + seconds);
        seconds = seconds - 1;
    }
}

jQuery(function($) {
      // Once document is ready, find the #countdown element, and cache it
   $countdown = $('#countdown');
      // retain reference to the setInterval call
   interval = setInterval(updateCountdown,1000);
});

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