我有一个HTML，它有一些带有冒号的元素，例如，

<div id="i:have:colons">Get my selector!!</div>
<my:another:test> This time with tag names </my:another:test>

我想使用jQuery选择这些元素。下面是我的几次尝试和Jsbin Demo

function escape(id) {
  return id.replace( /(:|\.|\[|\])/g, '\\$1');
}

var id = "i:have:colons";

// Does not work
console.log($('#' + id).length);

// Works
console.log($("#i\\:have\\:colons").length);

var escapedId = escape(id);

// Q1. Why answer shows only 1 backslash while I used 2 in regex
console.log(escapedId); //'i\:have\:colons'

// Works
console.log($('#' + escapedId).length);

// Q2. Does not work while escapedId === 'i\:have\:colons'. How and why ?
console.log($('#' + 'i\:have\:colons').length);

T.J回答后编辑

var tag = 'my:another:test';

console.log('Testing tag name now----');

console.log($(tag).length);

var tag2 = tag.replace(/[:]/g, '\\\\:');

// Does not work with tagnames but this works with Id
console.log($(tag2).length);

var tag3 = tag.replace(/[:]/g, '\\:');

// Q3. Why does this work with tagnames but not with ids ?
console.log($(tag3).length);

我的问题在JS代码的注解中。