代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>includes</title>
<script>
String.prototype.include2=function (data) {
var length = this.length;
var dataLength=data.length;
//当字符串的长度小于传入要比较的字符串小，直接 return false
if(dataLength>length){
return false;
}else{
let size =length-dataLength;
for(let i=0;i<size;i++){
let index=0;
while(this[i+index]==data[index]&&index<dataLength){
index++;
}
if(index==dataLength){
return true;
}
}
return false;
}
}
let data = 'oooHello world!';
console.log(data.include2('Hello2'));
</script>
</head>
<body>
</body>
</html>结果：
