as3.0 简单计算器

import flash.events.MouseEvent;

txt.background = true;

txt.backgroundColor = 0x006600;

var bian1:String,bian2:String,bian3:String;
var bian4:Boolean ;
txt.textColor = 0x000000;
txt.selectable = false;
btn_1.addEventListener(MouseEvent.CLICK,onbtn_1);
btn_2.addEventListener(MouseEvent.CLICK,onbtn_2);
btn_3.addEventListener(MouseEvent.CLICK,onbtn_3);
btn_4.addEventListener(MouseEvent.CLICK,onbtn_4);
btn_5.addEventListener(MouseEvent.CLICK,onbtn_5);
btn_6.addEventListener(MouseEvent.CLICK,onbtn_6);
btn_7.addEventListener(MouseEvent.CLICK,onbtn_7);
btn_8.addEventListener(MouseEvent.CLICK,onbtn_8);
btn_9.addEventListener(MouseEvent.CLICK,onbtn_9);
btn_0.addEventListener(MouseEvent.CLICK,onbtn_0);
btn.addEventListener(MouseEvent.CLICK,onbtn);
btn_jia.addEventListener(MouseEvent.CLICK,onbtn_Jia);
btn_jian.addEventListener(MouseEvent.CLICK,onbtn_Jian);
btn_cheng.addEventListener(MouseEvent.CLICK,onbtn_Cheng);
btn_chu.addEventListener(MouseEvent.CLICK,onbtn_Chu);
btn_deng.addEventListener(MouseEvent.CLICK,onbtn_Deng);
btn_clear.addEventListener(MouseEvent.CLICK,onbtn_Clear);
function onbtn_1(e:MouseEvent ):void
{ if (bian4 == true)
{
txt.text ="";

bian4 = false;

}
txt.appendText("1");


}

function onbtn_2(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text ="";
bian4 = false;
}
txt.appendText("2");
}

function onbtn_3(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("3");
}

function onbtn_4(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("4");
}

function onbtn_5(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("5");
}

function onbtn_6(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("6");
}

function onbtn_7(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("7");
}

function onbtn_8(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("8");
}

function onbtn_9(e:MouseEvent ):void
{ if(bian4 == true)
{
txt.text = "";
bian4 = false;
}
txt.appendText("9");
}

function onbtn_0(e:MouseEvent ):void
{
txt.appendText("0");
}

function onbtn(e:MouseEvent ):void
{
txt.appendText(".");
}

function onbtn_Jia(e:MouseEvent ):void
{
bian1 = txt.text;
txt.text = "";
bian3 = "+";

}

function onbtn_Jian(e:MouseEvent ):void
{
bian1 = txt.text;
txt.text = "";
bian3 = "-";
}

function onbtn_Cheng(e:MouseEvent ):void
{
bian1 = txt.text;
txt.text = "";
bian3 = "*";
}

function onbtn_Chu(e:MouseEvent ):void
{
bian1 = txt.text;
txt.text = "";
bian3 = "/";
}

function onbtn_Deng(e:MouseEvent ):void
{ bian4 = true;
if (bian3=="+")
{
bian2=String(Number(bian1)+Number(txt.text));
txt.text = "";
txt.text = bian2;

}
if (bian3=="-")
{
bian2=String(Number(bian1)-Number(txt.text));
txt.text = "";
txt.text = bian2;
}
if (bian3=="*")
{
bian2=String(Number(bian1)*Number(txt.text));
txt.text = "";
txt.text = bian2;
}
if (bian3=="/")
{
bian2=String(Number(bian1)/Number(txt.text));
txt.text = "";
txt.text = bian2;
}
bian1 = "0";

}

function onbtn_Clear(e:MouseEvent ):void
{
txt.text = "";

}