可以将以下代码放入editplus里建一个html文件直接运行!<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "https://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312" /><title>switch...case语句与if...else性能比较</title><script type="text/javascript">//声明一点,switch语句只能比较常量,而if语句可以比较复杂的表达式//可以通过几个常用的浏览器测试,会得到不同的结果var count=99999;function nIfElseTest(num){var dBegin=new Date;//进行var iNum=0;for(var i=0;i<count;i++){if(num==0){iNum=0;}else if(num==1){iNum=0;}else if(num==2){iNum=0;}else if(num==3){iNum=0;}else if(num==4){iNum=0;}else if(num==5){iNum=0;}else if(num==6){iNum=0;}else if(num==7){iNum=0;}else if(num==8){iNum=0;}else if(num==9){iNum=0;}else if(num==10){iNum=0;}else if(num==11){iNum=0;}else if(num==12){iNum=0;}else if(num==13){iNum=0;}else if(num==14){iNum=0;}else if(num==15){iNum=0;}else if(num==16){iNum=0;}else if(num==17){iNum=0;}else if(num==18){iNum=0;}}var dEnd=new Date;document.write("if...else耗时"+(dEnd.getTime()-dBegin.getTime())+"毫秒"+",num="+num+"<a href='/go.html?url=javascript:history.back()'>继续测试</a>");}function nSwitchCaseTest(num){var dBegin=new Date;//进行for(var i=0;i<count;i++){switch(num){case 0: iNum=0;break;case 1: iNum=0;break;case 2: iNum=0;break;case 3: iNum=0;break;case 4: iNum=0;break;case 5: iNum=0;break;case 6: iNum=0;break;case 7: iNum=0;break;case 8: iNum=0;break;case 9: iNum=0;break;case 10: iNum=0;break;case 11: iNum=0;break;case 12: iNum=0;break;case 13: iNum=0;break;case 14: iNum=0;break;case 15: iNum=0;break;case 16: iNum=0;break;case 17: iNum=0;break;case 18: iNum=0;break;default:}}var dEnd=new Date;document.write("switch_case耗时"+(dEnd.getTime()-dBegin.getTime())+"毫秒"+",num="+num+"<a href='/go.html?url=javascript:history.back()'>继续测试</a>");}</script></head><body><button onClick="javaScript:nIfElseTest(0)">if0</button> <button onClick="javaScript:nIfElseTest(2)">if2</button> <button onClick="javaScript:nIfElseTest(4)">if4</button> <button onClick="javaScript:nIfElseTest(6)">if6</button> <button onClick="javaScript:nIfElseTest(8)">if8</button> <button onClick="javaScript:nIfElseTest(10)">if10</button> <button onClick="javaScript:nIfElseTest(12)">if12</button> <button onClick="javaScript:nIfElseTest(14)">if14</button> <button onClick="javaScript:nIfElseTest(16)">if16</button> <button onClick="javaScript:nIfElseTest(18)">if18</button><p><a href="/go.html?url=https://www.dreamdu.com/javascript/switch_case/">switch...case</a>测试</p><button onClick="javaScript:nSwitchCaseTest(0)">switch0</button><button onClick="javaScript:nSwitchCaseTest(2)">switch2</button><button onClick="javaScript:nSwitchCaseTest(4)">switch4</button><button onClick="javaScript:nSwitchCaseTest(6)">switch6</button><button onClick="javaScript:nSwitchCaseTest(8)">switch8</button><button onClick="javaScript:nSwitchCaseTest(10)">switch10</button><button onClick="javaScript:nSwitchCaseTest(12)">switch12</button><button onClick="javaScript:nSwitchCaseTest(14)">switch14</button><button onClick="javaScript:nSwitchCaseTest(16)">switch16</button><button onClick="javaScript:nSwitchCaseTest(18)">switch18</button></body></html><!DOCTYPE html 你的当前访问异常,请进行认证后继续阅读剩余内容。 提交