want to increase value by mouse on (release)

my script is ................

import flash.external.*; //so we can use externalInterface

import QueryString.as;   //so we can use the QueryString Class

var myPath:QueryString = new QueryString();

assignVariables();

//custom function to handle all the query string parameters

function assignVariables() {

    //if myName parameter exists

    if (myPath.parameters.m1) {

        //assign it to the text of the myName text box

        //unescape() will translate/unencode the url characters

        myName.text = unescape(myPath.parameters.m1);

    }

    if (myPath.parameters.m2) {

        thisUrl.text = unescape(myPath.parameters.m2);

    }

    if (myPath.url) {

        //get the complete url (including any parameters)

        thisUrl.text = myPath.url;

    }

}

var st=12;

thisUrl.text=st;

my button script is----

on(release){

    st = st+10;

}