input select(multiple) implements drop-down box input value_javascript skills

So I tried to use input select to achieve it, and the results are as follows:

Detailed code and demonstration address: www.homdian.com/test.aspx

This method actually presses a text box on the drop-down box, which can realize input and selection of the drop-down box. But when binding the drop-down box options asynchronously based on the input value,

Unable to expand the drop-down box, I found a piece of code online:

The above paragraph can expand the drop-down box, but the following prompt will pop up (test environment IE7)

It feels unfriendly, so it’s useless. So I tried to use input select(multiple), the effect is as follows:

Detailed code and demonstration address: www.homdian.com/test1.aspx

This method basically meets my needs, so I post it here in the hope that everyone can provide a better method. Thanks.