html實現(xiàn)簡單計算器附詳細(xì)思路

字號:


    代碼如下:
    <!doctype html>
    <html>
    <meta name=content-type content=text/html; charset=utf-8>
    <head>
    <title>calculator</title>
    <!--將按鍵內(nèi)容以字符串形式存儲在文字框中當(dāng)按鈕為“=”時,調(diào)用eval方法計算結(jié)果然后將結(jié)果輸出文字框中-->
    <script type=text/javascript>
    var numresult;
    var str;
    function onclicknum(nums) {
    str = document.getelementbyid(nummessege);
    str.value = str.value + nums;
    }
    function onclickclear() {
    str = document.getelementbyid(nummessege);
    str.value = ;
    }
    function onclickresult() {
    str = document.getelementbyid(nummessege);
    numresult = eval(str.value);
    str.value = numresult;
    }
    </script>
    </head>
    <body bgcolor=affff >
    <!--定義按鍵表格,每個按鍵對應(yīng)一個事件觸發(fā)-->
    <table border=1 bgcolor=#bbff77
    style=height: 350px; width: 270px>
    <tr>
    <td colspan=4>
    <input type=text id=nummessege
    style=height: 90px; width: 350px; font-size: 50px />
    </td>
    </tr>
    <tr>
    <td>
    <input type=button value=1 id=1 onclick=onclicknum(1)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=2 id=2 onclick=onclicknum(2)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=3 id=3 onclick=onclicknum(3)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=+ id=add onclick=onclicknum('+')
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    </tr>
    <tr>
    <td>
    <input type=button value=4 id=4 onclick=onclicknum(4)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=5 id=5 onclick=onclicknum(5)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=6 id=6 onclick=onclicknum(6)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=- id=sub onclick=onclicknum('-')
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    </tr>
    <tr>
    <td>
    <input type=button value=7 id=7 onclick=onclicknum(7)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=8 id=8 onclick=onclicknum(8)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=9 id=9 onclick=onclicknum(9)
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=* id=mul onclick=onclicknum('*')
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    </tr>
    <tr>
    <td colspan=2>
    <input type=button value=0 id=0 onclick=onclicknum(0)
    style=height: 70px; width: 190px; font-size: 35px>
    </td>
    <td>
    <input type=button value=. id=point onclick=onclicknum('.')
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    <td>
    <input type=button value=/ id=division
    onclick=onclicknum('/')
    style=height: 70px; width: 90px; font-size: 35px>
    </td>
    </tr>
    <tr>
    <td colspan=2>
    <input type=button value=del id=clear
    onclick=onclickclear()
    style=height: 70px; width: 190px; font-size: 35px />
    </td>
    <td colspan=2>
    <input type=button value== id=result
    onclick=onclickresult()
    style=height: 70px; width: 190px; font-size: 35px />
    </td>
    </tr>
    </table>
    </body>
    </html>