How to use indexOf in JavaScript
If you want to retrieve whether a string contains a certain character? In this case, you can use the indexOf function, which returns the first occurrence of a specified string value in the string.
#The indexOf function searches a string for a specified character and, if present, returns the position.
How to use indexOf function
The basic procedure is as follows
String.indexOf( 检索的字符[, 检索开始的位置])
Use indexOf to search strings
The code is as follows
<!DOCTYPE html>
<html lang = "ja">
<head>
<meta charset = "utf-8">
<title>How to use indexOf in How to use indexOf in JavaScript</title>
</head>
<body>
<script>
var str1 = '英语,中文,法语,阿拉伯语,中文';
var index1 = str1.indexOf('中文');
console.log(index1);
var index2 = str1.indexOf('中文', 7);
console.log(index2);
var array1 = [ '张三', '李四', '王二', '陈五' ];
var index3 = array1.indexOf('李四');
console.log(index3);
</script>
</body>
</html>The running results are as follows
var str1 = '英语,中文,法语,阿拉伯语,中文'; var index1 = str1.indexOf('中文'); console.log(index1); var index2 = str1.indexOf('中文', 7); console.log(index2);
var array1 = [ '张三', '李四', '王二', '陈五' ]; var index3 = array1.indexOf('李四'); console.log(index3);
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