[IE & FireFox compatibility] JS special effects on select operations _ forms

[IE & amp; FireFox compatibility] JS uses two drop-down boxes in Ajax to dynamically add options in select, I am not very familiar with the script when I use it normally in IE testing but cannot use it in FireFox. So I checked it online and found that they were a little different when I added option dynamically.

Let's take a look at it and try again later:

Dynamically delete all options in the select statement:
Function deleteAllOptions (sel ){
Sel. options. length = 0;
}

Dynamically delete an option in the select statement:
Function deleteOption (sel, indx ){
Sel. options. remove (indx );
}

Dynamically Add the option in the select statement:
Function addOption (sel, text, value ){
Sel. options. add (new Option (text, value ));
}

Both IE and FireFox can be tested successfully. I hope you can use it later.
You can also use standard DOM operations, such as document. createElement, appendChild, and removeChild. :)