<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="jquery-1.12.4.js"></script>
</head>
<body>
原字符串:<input id="string">
需要查找的字符串:<input id="str">
<button id="find">查找</button>
<script>
$("#find").click(function(){
var string = $("#string").val();
var str = $("#str").val();
var arr = Array.from(string);
console.log(arr)
var num = 0
for(var i = 0; i < arr.length; i++){
if(str == arr[i]){
num++
}
}
alert(str+"在"+string+"中出现了"+num+"次")
})
</script>
</body>
</html>