实现代码：
<html> <head> <script> function calc(event){ // test //window.alert(event.value); var val = new String(event.value); // clear space val = val.trim(); var res = document.getElementById("res"); // clear if(val == "clear"){ res.value = ""; } // back if(val == "back"){ res.value = res.value.substring(0, res.value.length - 1); } // power if(val == "power"){ val = "p"; } // add val to text if(val.length == 1 && val != "="){ res.value = res.value + val; } // calc result if(val == "="){ var arr; var result; // power if(res.value.indexOf("p") != -1){ arr = res.value.split("p"); //window.alert(arr); result = Math.pow(parseFloat(arr[0]) ,parseFloat(arr[1])); //window.alert(res); res.value = result; } // plus if(res.value.indexOf("+") != -1){ arr = res.value.split("+"); //window.alert(arr); result = parseFloat(arr[0]) + parseFloat(arr[1]); //window.alert(res); res.value = result; } else if(res.value.indexOf("-") != -1){ // minus arr = res.value.split("-"); //window.alert(arr); result = parseFloat(arr[0]) - parseFloat(arr[1]); //window.alert(res); res.value = result; } else if(res.value.indexOf("*") != -1){ // multiply arr = res.value.split("*"); //window.alert(arr); result = parseFloat(arr[0]) * parseFloat(arr[1]); //window.alert(res); res.value = result; } else if(res.value.indexOf("https://www.jb51.net/") != -1){ // division arr = res.value.split("https://www.jb51.net/"); //window.alert(arr); result = parseFloat(arr[0]) / parseFloat(arr[1]); //window.alert(res); res.value = result; } else if(res.value.indexOf("%") != -1){ // module arr = res.value.split("%"); //window.alert(arr); result = parseFloat(arr[0]) % parseFloat(arr[1]); //window.alert(res); res.value = result; } } } </script> </head> <body> <table cellpadding="10px" cellspacing="5px"> <tr> <td colspan="4"><input type="text" size="35px" value=""/></td> </tr> <tr> <td><input type="button" value="power"/></td> <td><input type="button" value="clear"/></td> <td colspan="2"><input type="button" value=" back "/></td> </tr> <tr> <td><input type="button" value=" 1 "/></td> <td><input type="button" value=" 2 "/></td> <td><input type="button" value=" 3 "/></td> <td><input type="button" value=" + "/></td> </tr> <tr> <td><input type="button" value=" 4 "/></td> <td><input type="button" value=" 5 "/></td> <td><input type="button" value=" 6 "/></td> <td><input type="button" value=" - "/></td> </tr> <tr> <td><input type="button" value=" 7 "/></td> <td><input type="button" value=" 8 "/></td> <td><input type="button" value=" 9 "/></td> <td><input type="button" value=" * "/></td> </tr> <tr> <td><input type="button" value=" 0 "/></td> <td><input type="button" value=" = "/></td> <td><input type="button" value=" % "/></td> <td><input type="button" value=" / "/></td> </tr> </table> </body> </html>