JS determines whether a string contains a string, finds a substring in the string object, IndexOf

1 var Cts = "Bbltext"; 2  3 if (Cts.indexof ("Text") > 0 ) 4 {5     alert (' CTS contains text string '); 6 }

indexof Usage:

returns the character position of a substring within a string object for the first time.

Strobj.indexof (substring[, StartIndex])

Parameters
Strobj

Required Options。 A String object or literal.

subString

Required Options。 The substring to find in the string object.

Starindex

options available。 The integer value that indicates the index at which to start the lookup within a String object. If omitted, it is searched from the beginning of the string.

Description
The IndexOf method returns an integer value that indicates the starting position of the substring in the string object. If no substring is found, 1 is returned.

If the startindex is negative, then startindex is treated as zero. If it is larger than the maximum character position index, it is treated as the largest possible index.

Performs a lookup from left to right. Otherwise, the method is the same as lastIndexOf.

Example
The following example illustrates the use of the IndexOf method.

1    function  2     var3     var s = str1.  4     return  5    

IndexOf ignoring case for JavaScript

The IndexOf function method in JavaScript returns an integer value that indicates where the substring of a string object begins. If no substring is found, 1 is returned. If the startindex is negative, then startindex is treated as zero. If it is larger than the maximum character position index, it is treated as the largest possible index.

The IndexOf function performs a lookup from left to right. Otherwise, the method is the same as lastIndexOf.

The following example illustrates the use of the IndexOf function method.

1 function Indexdemo (str2) {2    var str1 = "Babebibobubabebibobu"3    var s = str1.  IndexOf (STR2); 4    return (s); 5 }

JS determines whether a string contains a string, finds a substring in the string object, IndexOf