JavaScript indexOf () method
Examples
Search string "welcome":
var str="Hello world, welcome to the universe.";
var n=str.indexOf("welcome");
var n=str.indexOf("welcome");
n output:
try it"
Definition and Usage
indexOf () method returns the position of a string value of the first occurrence of the specified string.
If no matching string found -1 is returned.
Note: indexOf () method is case-sensitive.
Tip: You can also view a similar manner lastIndexOf () .
Browser Support
All major browsers support indexOf () method.
grammar
string.indexOf( searchvalue , start )
Parameter Value
| 参数 | 描述 |
|---|---|
| searchvalue | 必需。规定需检索的字符串值。 |
| start | 可选的整数参数。规定在字符串中开始检索的位置。它的合法取值是 0 到 string Object.length - 1。如省略该参数，则将从字符串的首字符开始检索。 |
return value
| 类型 | 描述 |
|---|---|
| Number | 查找指定字符串第一次出现的位置，如果没找到匹配的字符串则返回 -1。 |
technical details
| JavaScript version: | 1.0 |
|---|
More examples
Examples
Find the string of characters "e" for the first time to appear:
var str="Hello world, welcome to the universe.";
var n=str.indexOf("e");
var n=str.indexOf("e");
n output:
try it"
Examples
The fifth position in the string Find position of the character "e" first appears:
var str="Hello world, welcome to the universe.";
var n=str.indexOf("e",5);
var n=str.indexOf("e",5);
n output:
try it"