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javascript计算器

来源:网络 作者:佚名 点击: 时间:2017-05-07 08:34
[摘要] html head title计算器/title /head body bgcolor="#ffffff" onload="FKeyPad.ReadOut.focus();FKeyPad.ReadOut.select();" FORM name="Keypad" action="" TABLE align="center" B TABLE align="center" border=2 width=50 height=60 cellpadding=1 cellspa
<html>
<head>
<title>计算器</title>
</head>
<body bgcolor="#ffffff" onload="FKeyPad.ReadOut.focus();FKeyPad.ReadOut.select();">
<FORM name="Keypad" action="">
<TABLE align="center">
 <B>
 <TABLE align="center" border=2 width=50 height=60 cellpadding=1 cellspacing=5>
  <TR>
   <TD colspan=3 align=middle><input name="ReadOut" type="Text" onkeypress="CheckOut()" size=24 value="0" width=100%></TD>
   <TD></TD>
   <TD><input name="btnClear" type="Button" value="  C  " onclick="Clear()"></TD>
   <TD><input name="btnClearEntry" type="Button" value="  CE " onclick="ClearEntry()"></TD>
  </TR>
  <TR>
   <TD><input name="btnSeven" type="Button" value="  7  " onclick="NumPressed(7)"></TD>
   <TD><input name="btnEight" type="Button" value="  8  " onclick="NumPressed(8)"></TD>
   <TD><input name="btnNine" type="Button" value="  9  " onclick="NumPressed(9)"></TD>
   <TD></TD>
   <TD><input name="btnNeg" type="Button" value=" +/- " onclick="Neg()"></TD>
   <TD><input name="btnPercent" type="Button" value="  %  " onclick="Percent()"></TD>
  </TR>
  <TR>
   <TD><input name="btnFour" type="Button" value="  4  " onclick="NumPressed(4)"></TD>
   <TD><input name="btnFive" type="Button" value="  5  " onclick="NumPressed(5)"></TD>
   <TD><input name="btnSix" type="Button" value="  6  " onclick="NumPressed(6)"></TD>
   <TD></TD>
   <TD align=middle><input name="btnPlus" type="Button" value="  +  " onclick="Operation('+')"> </TD>
   <TD align=middle><input name="btnMinus" type="Button" value="  -  " onclick="Operation('-')"></TD>
  </TR>
  <TR>
   <TD><input name="btnOne" type="Button" value="  1  " onclick="NumPressed(1)"></TD>
   <TD><input name="btnTwo" type="Button" value="  2  " onclick="NumPressed(2)"></TD>
   <TD><input name="btnThree" type="Button" value="  3  " onclick="NumPressed(3)"></TD>
   <TD></TD>
   <TD align=middle><input name="btnMultiply" type="Button" value="  *  " onclick="Operation('*')"></TD>
   <TD align=middle><input name="btnDivide" type="Button" value="  /  " onclick="Operation('/')"></TD>
  </TR>
  <TR>
   <TD><input name="btnZero" type="Button" value="  0  " onclick="NumPressed(0)"></TD>
   <TD><input name="btnDecimal" type="Button" value="  .  " onclick="Decimal()"></TD>
   <TD colspan=2></TD>
   <TD><input name="btnEquals" type="Button" value="  =  " onclick="Operation('=')"></TD>
   <TD><input name="btnReturn" type="Button" value="返 回" onclick="goReturn()"></TD>
  </TR>
 </TABLE>
</TABLE>
</B>
</FORM>
</CENTER>
<font face="Verdana, Arial, Helvetica" size=2>
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
var FKeyPad = document.forms['Keypad'];
var Accum = "0";
var FlagNewNum = false;
var PendingOp = "";

//===============================================================================
//[描述] 浮点数精确计算
//[参数]     str1 - 第一个数
//   str2 - 第二个数
//   type - 运算符
//   precision - 小数位精度
//[调用方式]   longCount(str1,str2,type,precision);
//[返回值]   计算结果
//===============================================================================
    function longCount(str1,str2,type) {
        var comma1 = 0;
        if (str1.indexOf(".")!=-1) {
            str1 = str1.replace(/0*$/,"");
            comma1 = str1.length - str1.indexOf(".")-1;
        }
        var comma2 = 0;
        if (str2.indexOf(".")!=-1) {
            str2 = str2.replace(/0*$/,"");
            comma2 = str2.length - str2.indexOf(".")-1;
        }
        str1 = str1.replace(/\./,"");
        str2 = str2.replace(/\./,"");
        var value,comma;
        if (type!="*") {
            if (comma1>comma2) {
                for (var i=0;i<comma1-comma2;i++) str2 += "0";
                comma = (type=="/")?0:comma1;
            }else {
                for (var i=0;i<comma2-comma1;i++) str1 += "0";
                comma = (type=="/")?0:comma2;
            }
        }else {
            comma = comma1 + comma2;
        }
        if (type=="+") {
            value = parseInt(str1,10) + parseInt(str2,10);
        }else if (type=="-") {
            value = parseInt(str1,10) - parseInt(str2,10);
        }else if (type=="*") {
            value = parseInt(str1,10) * parseInt(str2,10);
        }else if (type=="/") {
            value = parseInt(str1,10) / parseInt(str2,10);
        }
        value = String(value);
        if (comma>0) value = value.substring(0,value.length-comma)+"."+value.substring(value.length-comma,value.length);
        if (value.indexOf(".")!=-1)
            value = value.replace(/0*$/,"");
        return value;
    }
function NumPressed (Num) {
 if (FlagNewNum) {
  FKeyPad.ReadOut.value  = Num;
  FlagNewNum = false;
   }
 else {
  if (FKeyPad.ReadOut.value == "0")
   FKeyPad.ReadOut.value = Num;
  else
   FKeyPad.ReadOut.value += Num;
   }
}
function Operation (Op) {
 var Readout = FKeyPad.ReadOut.value;
 if (FlagNewNum && PendingOp != "=");
 else
 {
  FlagNewNum = true;
  if ( '+' == PendingOp || '-' == PendingOp || '/' == PendingOp || '*' == PendingOp)
   Accum = longCount(Accum,Readout,PendingOp);
  else
   Accum = Readout;
        FKeyPad.ReadOut.value = Accum;
        PendingOp = Op;
        FKeyPad.ReadOut.focus();
        FKeyPad.ReadOut.select();
 }
}
function Decimal () {
 var curReadOut = FKeyPad.ReadOut.value;
 if (FlagNewNum) {
  curReadOut = "0.";
  FlagNewNum = false;
   }
 else
 {
  if (curReadOut.indexOf(".") == -1)
   curReadOut += ".";
   }
 FKeyPad.ReadOut.value = curReadOut;
}
function ClearEntry () {
 FKeyPad.ReadOut.value = "0";
 FlagNewNum = true;
}
function Clear () {
 Accum = "0";
 PendingOp = "";
 ClearEntry();
}
function Neg () {
    alert(FKeyPad.ReadOut.value);
 FKeyPad.ReadOut.value = longCount(FKeyPad.ReadOut.value,"-1","*");
}
function Percent () {
 FKeyPad.ReadOut.value = longCount(FKeyPad.ReadOut.value,Accum,"*");
 FKeyPad.ReadOut.value = longCount(FKeyPad.ReadOut.value,100,"/");
}
function goReturn() {
    top.returnValue = FKeyPad.ReadOut.value;
    self.close();
}
function CheckOut() {
    var keyCode = window.event.keyCode;
    if (keyCode>=48 && keyCode<=57) {
  if (FlagNewNum) {
   FKeyPad.ReadOut.value  = "";
   //window.event.keyCode = null;
   FlagNewNum = false;
  }
        return true;
    }else if (keyCode==43 || keyCode==45 || keyCode==42 || keyCode==47 || keyCode==61) {
        Operation(String.fromCharCode(keyCode));
    }else if (keyCode==46) {//.
        if (FKeyPad.ReadOut.value.indexOf(".") == -1)
         return true;
    }else if (keyCode==13) goReturn();
    window.event.returnValue = false;
    return false;
}
// End -->
</SCRIPT>
</body>
</html>

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