8th Week 1
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>查询字符串次数</title> </head> <body> <button onclick="myFunction()">点击查询字符串中"first"字符出现的次数</button> <p ></p> <script type="text/javascript"> function myFunction() { var str = "first,second,third,first,speed,first,flexible,first,third"; var count=0; var index=0; var key="first"; while((index = str.indexOf(key,index))!= -1) { index += key.length; count = count+1; } document.getElementById("demo").innerHTML = count; } </script> </body> </html>