<!DOCTYPE html><html><head><title>14th_test</title><meta charset="gb2312"></head> <body><h1>这是一个标题</h1><p>以下是一个简易计算器</p> <table border="1" style="position:center;"><tr><th>第一个数</th><td><input id="fir" type="text" /></td></tr> <tr><th>第二个数</th><td><input id="sec" type="text" /></td></tr> <tr><td colspan="2"><button type="button" οnclick="add()">+</button><button type="button" οnclick="substract()">-</button><button type="button" οnclick="multiply()">*</button><button type="button" οnclick="divide()">/</button></td></tr> <tr><td colspan="2"><p id="result"></p></td></tr></table> <script>var res; //保存计算结果function add(){var first = document.getElementById("fir").value;var second = document.getElementById("sec").value; res = Number(first) + Number(second); //这里"+"两端必须Number类型转换，否则当成字符串连接 sent(res);} function substract(){var first = document.getElementById("fir").value;var second = document.getElementById("sec").value; res = first - second; sent(res);} function multiply(){var first = document.getElementById("fir").value;var second = document.getElementById("sec").value; res = first * second; sent(res);} function divide(){var first = document.getElementById("fir").value;var second = document.getElementById("sec").value; res = first / second; sent(res);} function sent(re){ document.getElementById("result").innerHTML = re;}</script></body></html>
