JS acquisition, addition, and deletion operations for HTML tag select_javascript skills-js tutorial

The code is as follows:

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The code is as follows:

//Get the html control
var select = document.getElementsByName(“aaa”)[0];

select.selectedIndex = index;
//Create a new Option object
new Option(text,value)
new option(text,value,defaultSelected,selected
text: string, specifying the text attribute of the option object (that is, the text between )
value: String, specifies the value attribute of the option object
defaultSelected: Boolean value, specifies the defaultSelected attribute of the option object
selected: Boolean value, specifies the selected attribute of the option object

// Add Option to select
select.add(new Option(text,value))

//Delete
select.options.remove(index)
//Delete all at once
select.length = 0;