用typeof查看数据类型&&用parseInt解析数字，并求和

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<pre>

&lt;script type="text/javascript"&gt;

    alert(typeof 12345);    <span>//输出number</span>

    alert(typeof "abc");    <span>//输出string</span>

    alert(typeof document);    <span>//输出object</span>

&lt;/script&gt;

</pre>

<script>

alert("typeof 12345 → " + typeof 12345 + "\

      \n\ntypeof \"abc\" → " + typeof "abc" + "\

      \n\ntypeof document → " + typeof document

      );

</script>

</body>

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用parseInt解析数字，并求和

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<title>用parseInt解析数字，并求和</title>

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.f-text{width:50px;border:1px solid #ccc;background:#f0f0f0;font-family:inherit;padding:3px;}

span{color:green;padding-right:10px;font-weight:700;}

strong{padding:0 10px;}

</style>

<script type="text/javascript">

window.onload = function ()

{

    var aInput = document.getElementsByTagName("input");

    var aSpan = document.getElementsByTagName("span")[0];

    var i = 0;

    for (i = 0; i < aInput.length - 1; i++)

    {

        aInput[i].onkeyup = function ()

        {

            this.value = this.value.replace(/[^\d]/,"")

        }

    }

    aInput[2].onclick = function ()

    {

        (aInput[0].value == "" || aInput[1].value == "") ?

        alert("请输入数字！") :

        aSpan.innerHTML = parseInt(aInput[0].value) + parseInt(aInput[1].value);

    }

};

</script>

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<input type="text" class="f-text" /><strong>+</strong><input type="text" class="f-text" /><strong>=</strong><span>?</span><input type="button" value="求和" />

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用typeof查看数据类型&&用parseInt解析数字，并求和

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