Javascript Convert String to Object

[MiglioreTech]

All -

I know this has to have been answered thousands of times in the annals of history but:

if I have a string representation of a select element (dropdown):

var str_select = "<select id='test'><option value='1'>Test</option></select>";

and I want to treat this an an dropdown object instead of a string, then traverse through the options as such, what is the best way? The same for other elements e.g.

str_div = "<div>Some Code</div>";

Thanks!