<!DOCTYPE?html>
<html>
<head>
????<title>?事件</title>
</head>
<body>
????<input?type='text'?id='txt1'?/>
????<select?id='select'>
????????<option?value='+'>+</option>
????????<option?value="-">-</option>
????????<option?value="*">*</option>
????????<option?value="/">/</option>
????</select>
????<input?type='text'?id='txt2'?/>
????<input?type='button'?value='?=?'?onclick="count()"?/>
????<!--通過?=?按鈕來調(diào)用創(chuàng)建的函數(shù)，得到結(jié)果-->
????<input?type='text'?id='fruit'?/>
????<script?type="text/javascript">
????????var?a?=?parseInt(document.getElementById('txt1')).value;
????????var?b?=?parseInt(document.getElementById('txt2')).value;
????????var?c?=?document.getElementById('select').value;
????????var?d;
????????function?count()?{
????????????if?(c?==?'+')?{
????????????????d?=?a?+?b;
????????????????document.getElementById('fruit').value?=?d;
????????????}?else?if?(c?==?'-')?{
????????????????d?=?a?-?b;
????????????????document.getElementById('fruit').value?=?d;
????????????}?else?if?(c?==?'*')?{
????????????????d?=?a?*?b;
????????????????document.getElementById('fruit').value?=?d;
????????????}?else?if?(c?==?'/')?{
????????????????d?=?a?/?b;
????????????????document.getElementById('fruit').value?=?d;
????????????}?else?if?(isNaN(a)?||?isNaN(b))?{
????????????????alert('請輸入數(shù)字！');
????????????}?else?if?(a.length?==?0)?{
????????????????alert('請輸入數(shù)字！');
????????????}?else?if?(b.length?==?0)?{
????????????????alert('請輸入數(shù)字！');
????????????}?else?if?(b?==?0)?{
????????????????alert('除數(shù)不能為0！');
????????????}
????</script>
</body>
</html>為什么執(zhí)行一直有問題，輸出一直是NaN? ??
關(guān)于簡易計算器NaN的問題
karlmarx
2016-05-24 02:23:43
