在 jQuery 中使用带变量的 $ 背后是否有任何特定原因
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Is there any specific reason behind using $ with variable in jQuery
提问by Exception
I know it's a silly question but I am a bit confused with this. For example, if I have an input with an ID: rad1, is there any difference between below lines of code?
我知道这是一个愚蠢的问题，但我对此有点困惑。例如，如果我有一个带有 ID: 的输入，rad1下面的代码行之间有什么区别吗？
var $a = $('#rad1')
or
或者
var a = $('#rad1')
回答by gdoron is supporting Monica
No there is no real difference.
不，没有真正的区别。
It's just a convention that helps you remember that aisn't the DOM element but it's a jQuery object.
这只是一个约定，可以帮助您记住它a不是 DOM 元素，而是一个 jQuery 对象。
var a = document.getElementById('a');
a.innerHTML //fine
var $a = $('#a');
$a.html() // fine
Ohhh, and by the way, neither aor $aare good variable names ... you should use meaningful variable names not abc characters.
噢噢噢，顺便说一句，没有a或$a有良好的变量名...你应该使用有意义的变量名不ABC字符。
Read the jQuery info tagon this very same site:
阅读同一个站点上的jQuery 信息标签：
Variable Naming Conventions
变量命名约定
jQuery wrapped variables are usually named starting with '$' to distinguish them from standard JavaScript objects.
jQuery 包装的变量通常以“$”开头，以区别于标准 JavaScript 对象。
var $this = $(this);
回答by Chuck Norris
It's only for showing that it's a Jquery variable.
它只是为了表明它是一个 Jquery 变量。
Declaring $ayou're showing that your variable is for JQuery objects, it's just a notation. So the most readable thing will be to declare Jquery variable with $ notation
声明$a您正在展示您的变量用于 JQuery 对象，这只是一个符号。所以最易读的事情是用 $ 符号声明 Jquery 变量
var $obj=$("#obj");
And DOM element without $ notation
和没有 $ 符号的 DOM 元素
var obj = document.getElementById("obj");
回答by kinakuta
There's no difference. It's just a coding convention to help identify that the variable represents a jquery wrapped object.
没有区别。这只是一个编码约定，以帮助识别变量代表 jquery 包装的对象。
回答by Govind Malviya
No difference its just coding convention , check this
没有区别只是编码约定，检查这个
回答by ylev
A composition also works fine:
组合也可以正常工作：
You can also do something like this to show a <div>:
你也可以做这样的事情来显示<div>：
function getCompTable(divId){
var $d = $('#' + divId);
$d.show();
}
USAGE
用法
getCompTable('compListDiv'); // compListDiv - is a div id=""
Yosi Lev
约西列夫
回答by Shiv
I think this scenario should illustrate the reason for remembering(off course, assigning '$' ) jquery and simple javascript variables:
我认为这种情况应该说明记住（当然，分配 '$' ）jquery 和简单的 javascript 变量的原因：
<form id='myform' >
<input id="name" type="text" value="Peter" />
</form>
<script>
$(document).ready(function(){
var name = document.getElementById('name');
var $name = $('#name');
console.log(name.value); // javascript's properties are available
console.log($name.value); //it is undefined (worth of notice)
console.log(name.val()); // error! name.val is not a function ! (jquery function will not be available)
console.log($name.val()); // jquery functions are available
});
</script>
