Convert string to time

Use Date Class.

For example:

trace(new Date(Date.parse("Wed Apr 12 19:18:17 GMT-0400 2000")).toLocaleTimeString());

shows 07:18:00 PM in EST time zone

While this

trace(new Date(Date.parse("Wed Apr 12 07:18:00 GMT-0400 2000")).toLocaleTimeString());

shows 07:18:00 AM in EST time zone.

To format per your requirements use:

trace(new Date(Date.parse("Wed Apr 12 19:18:00 GMT-0400 2006")).toLocaleTimeString().match(/^(\d{2,}\:\d{2,})|\w+$/g).join("").toLocaleLowerCase());

which returns

07:18pm

do you really want a time (actually date) object or a string. 

if a date object:

function dateF(s:String):Date{

    return new Date(null,null,null,s.split(":")[0],s.split(":")[1]);

}

if a string:

function dateF(s:String):String{

var n:int = int(s.split(":")[0]);

if(n>12){

return (n-12)+s.split(":")[1]+"pm";

} else {

return n+s.split(":")[1]+"am";

}

}