The difference between ID and NAME in HTML

It can be said that almost everyone who has done web development has asked, what is the difference between the ID and Name of an element? Why do we need Name when we have ID? And we can also get the most classic answer: ID is like a person's ID number, and Name is like his name. ID is obviously unique, and Name can be repeated.

The answer to ID and Name in the above paragraph is too general. Let’s discuss it in detail below.

1. Both name and id can be used to call elements in html

When we need to access an html element in the page in a script, we usually specify the id or name of the HTML element

Under the WEB standard, any element in the HTML document can be accessed through getElementById(), getElementsByName(), and getElementsByTagName().

To access a specific element try to use the standard document.getElementById(id).

If there are more than two tags with the same name in a document, then document.getElementsByName(name) can obtain these elements to form an array.

To access tags, use the standard document.getElementByTagName(tag).

Note: The ID identifier is case-sensitive, while the name basically has no requirements and can even use numbers.

2. Under what circumstances must name be used?

1. Form elements (for example: form, input, textarea, select, button, etc.) are usually related to form submission. On the receiving page of the form, only elements with names are received. Elements assigned with ids cannot receive values ​​through the form.

2. The form elements checkbox and radio button usually correspond to multiple controls. In this case, the name attribute must be used to achieve grouping. The same group uses the same name. There will be no interference between the options of the two questions.

3. The name of the frame element (iframe, frame), used to specify targets in other iframes and frames.

4. Establish the anchor point in the page. We know that link is to obtain a page hyperlink. If the href attribute is not used, name is used instead, such as: , we get a page anchor.

5. When linking IMG elements and MAP elements, if you want to define the hotspot area of ​​IMG, you need to use its attribute usemap, so usemap="#name" (the name of the associated MAP element).

6. Attributes of certain specific elements, such as attribute, meta and param. For example, define parameters for Object or in Meta

3. Under what circumstances must id be used?

1. The association between label and form control. For example:

<label for="myInput">文本录入框</label>
<input id="myInput" type="text" />

2. ID can be used to set a css style. For example:

<style type="text/css">
#my
{
      font-size: 12px;
      color: red;
}
</style>
<p id="my">设置字体大小和颜色</p>

         

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