<?php
if ($_GET['hesap']) {
    $hesap = rawurldecode(trim($_GET['hesap']));
    preg_match('@([0-9]+)([\+\-\*\/]{1})([0-9]+)@', $hesap, $cikti);
    @eval('$sonuc = ' . $cikti[1] . ' ' . $cikti[2] . ' ' . $cikti[3] . ';');
    echo "<script>var sonuc = '{$sonuc}'; </script>";
}
?>
<style type="text/css">
form { margin: 0; padding: 0; }
#bosluk { font-size: 0; height: 6px; }
#hesap { 
    background: #eee; 
    width: 202px; 
    text-align: left;
    border: 1px solid #ccc;
}
.b {
    padding-left: 6px;
    padding-right: 6px;
    padding-top: 2px;
    padding-bottom: 2px;
    width: 38px;
}
.ic {
    padding: 15px;
    padding-top: 12px;
    text-align: center;
}
.ic2 {
    padding: 5px;
    text-align: center;
}
#giris {
    width: 168px;
    padding: 3px;
    padding-right: 5px;
    text-align: right;
}
</style>
<center>
<script type="text/javascript">
window.onload = function() {
    if (sonuc) document.getElementById('giris').value = sonuc;
}
function hesapla() {
    var sonuc = '', data = document.getElementById('giris').value;
    var regex = new RegExp("([0-9]+)([\-\+\*\/]{1})([0-9]+)"), match = regex.exec(data);
    var sayi1 = new Number(match[1]), sayi2 = new Number(match[3]);
    var operator = match[2], hesap = eval(sayi1 + operator + sayi2);
    document.getElementById('giris').value = hesap;
}
function preg_quote(str) {
    return (str + '').replace(/([\\\.\+\*\?\[\^\]\$\(\)\{\}\=\!<>\|\:])/g, "\\$1");
}
function ekle(gelen, sayi) {
    var giris = document.getElementById('giris');
    if (giris.value == '0') giris.value = '';
    if (sayi == 1) {
        if (!giris.value.match(preg_quote(gelen)) && giris.value != '')
            giris.value += gelen;
    } else {
        giris.value += gelen;
    }
}
function sil() {
    var giris = document.getElementById('giris');
    var len = giris.value.length;
    if (len != 0) {
        giris.value = giris.value.substr(0, len-1);
        return true;
    }
    return false;
}
</script>
<form action="" method="get">
    <div id="hesap" style="margin-top:10px; background: #e0e0e0; font: bold 13px tahoma; border-bottom: 0;">
        <div  class="ic2">
            Hesap Makinesi
        </div>
    </div>
    <div id="hesap">
        <div  class="ic">
            <input id="giris" type="text" name="hesap" value="0" />
            <div id="bosluk"></div>
            <input class="b" style="color:red; width:58px" type="button" onclick="sil();" value="Sil" />
            <input class="b" style="color:red; width:59px" onclick="document.getElementById('giris').value='';" type="button" value="CE" />
            <input class="b" onclick="ekle('/', 1);" style="color:red;" type="button" value="/" />
            <div id="bosluk"></div>
            <input class="b" onclick="ekle('7');" type="button" value="7" />
            <input class="b" onclick="ekle('8');" type="button" value="8" />
            <input class="b" onclick="ekle('9');" type="button" value="9" />
            <input class="b" onclick="ekle('*', 1);" style="color:red;" type="button" value="*" />   
            <div id="bosluk"></div>
            <input class="b" onclick="ekle('4');" type="button" value="4" />
            <input class="b" onclick="ekle('5');" type="button" value="5" />
            <input class="b" onclick="ekle('6');" type="button" value="6" />
            <input class="b" onclick="ekle('-', 1);" style="color:red;" type="button" value="-" />
            <div id="bosluk"></div>
            <input class="b" onclick="ekle('1');" type="button" value="1" />
            <input class="b" onclick="ekle('2');" type="button" value="2" />
            <input class="b" onclick="ekle('3');" type="button" value="3" />
            <input class="b" onclick="ekle('+', 1);" style="color:red;" type="button" value="+" />
            <div id="bosluk"></div>
            <input class="b" onclick="ekle('0');" type="button" value="0" />
            <input class="b" onclick="ekle('.', 1);" type="button" value="." />
            <input class="b" style="color:red; width:80px" type="button" onclick="hesapla();" value="=" />
        </div>
    </div>
</form>
</center>