超级简易的JS计算器（实现加减乘除）
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>简单的计算器</title> <style> body{ margin: 0; } .tab{ border: 3px solid black ; border-radius: 2px; border-collapse:collapse; width: 268px; height: 402px; margin: 100px auto; } .tr{ height: 67px; width: 268px; border: 3px solid black ; text-align: right; } .tr1{ width: 268px; height: 67px; border: 3px solid black ; text-align: center; } .tr2{ width: 67px; height: 67px; border: 3px solid black ; text-align: center; } </style> <script> var s1 = ""; var s2 = ""; var s3 = ""; var s4 = ""; var s5 = ""; function view(val){ var a = document.getElementById(val); s1 = a.innerHTML; if(s1=="+" || s1=="-" || s1=="*" || s1=="/"){ s3 = s1; s1 = ""; } if(s3=="+" || s3=="-" || s3=="*" || s3=="/"){ add2(s1); } if(s3==""){ add1(s1); } } function add1(s1){ s2 = s2 + s1; show(); } function add2(s1){ s4 = s4 + s1; show(); } function cal(){ switch(s3){ case "+":{ s5 = (String)((parseFloat(s2)+parseFloat(s4)).toFixed(2)); result.innerHTML = s5; break; } case "-":{ s5 = (String)((parseFloat(s2)-parseFloat(s4)).toFixed(2)); result.innerHTML = s5; break; } case "*":{ s5 = (String)((parseFloat(s2)*parseFloat(s4)).toFixed(2)); result.innerHTML = s5; break; } case "/":{ s5 = (String)((parseFloat(s2)/parseFloat(s4)).toFixed(2)); result.innerHTML = s5; break; } } } function show(){ var result = document.getElementById("result"); result.innerHTML = s2+s3+s4; } </script> </head> <body> <table class="tab"> <tr class = "tr2"> <td colspan="4">简易计算器</td> </tr> <tr class="tr"> <td id="result" colspan="4" > </td> </tr> <tr > <td id="+" class="tr1" onclick="view('+')">+</td> <td id="-" class="tr1" onclick="view('-')">-</td> <td id="*" class="tr1" onclick="view('*')">*</td> <td id="/" class="tr1" onclick="view('/')">/</td> </tr> <tr > <td id="7" class="tr1" onclick="view('7')">7</td> <td id="8" class="tr1" onclick="view('8')">8</td> <td id="9" class="tr1" onclick="view('9')">9</td> <td id="0" class="tr1" onclick="view('0')">0</td> </tr> <tr> <td id="4" class="tr1" onclick="view('4')">4</td> <td id="5" class="tr1" onclick="view('5')">5</td> <td id="6" class="tr1" onclick="view('6')">6</td> <td id="." class="tr1" onclick="view('.')">.</td> </tr> <tr> <td id="1" class="tr1" onclick="view('1')">1</td> <td id="2" class="tr1" onclick="view('2')">2</td> <td id="3" class="tr1" onclick="view('3')">3</td> <td id="=" class="tr1" onclick="cal()" >=</td> </tr> </table> </body> </html>
对于这个程序来说，判断的顺序非常重要，不然就会把"+"号存在s2，s4中而不是s3中。
