How does the HTML Select object operate on the Option object?

The content of this article is about how the HTML Select object operates the Option object. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

The select object is actually a composite object containing an array of option objects.

select object

The most important attribute of the select object is selectedIndex, which is the index value of the text in the currently selected box

Usage is:

formObject.selectName.selectedIndex

option object

Create an option object, that is, create one or more texts in the label

var a = document.getElementById("ID值");
a.options = new Option("文本", "值");

options is an array, which can store multiple text labels

Methods of the option object:

Add a label: obj.options.add(new Option("text", "value"))

Delete a label: obj.options.remove(obj .selectedIndex)

Get the text of a label: obj.options[obj.selectedIndex].text

Get the value of a label: obj.options[obj.selectedIndex].value

Modify the value of a tag: obj.options[obj.selectedIndex] = new Option("new text", "new value")

Delete all tags: obj.options.length = 0

Note: The option in obj.option does not need to be capitalized, and the Option in new Option needs to be capitalized

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