C# style: var item_names = $( "li.menu_item span" ).map( x => x.innerHTML )
JS style: var item_names = $( "li.menu_item span" ).map( function( x ) { return x.innerHTML } )
item_names = $("li.menu_item span").map (x) -> x.innerHTML
$("li.menu_item span").map(function(x) x.innerHTML)
for that particular exaple, you could also steal pluck() from Prototype.js:
$("li.menu_item span").pluck("innerHTML")
C# style: var item_names = $( "li.menu_item span" ).map( x => x.innerHTML )
JS style: var item_names = $( "li.menu_item span" ).map( function( x ) { return x.innerHTML } )