JS method to determine whether a string variable contains a specific string. js string

JS method to determine whether a string variable contains a specific string. js string

JS implementation method for determining whether a string variable contains a certain string

VarCts = "bblText"; if (Cts. indexOf ("Text")> 0) {alert ('cts contains the Text string ');}

IndexOf usage:

Returns the first occurrence of a substring in a String object.

StrObj. indexOf (subString [, startIndex])

Parameters

StrObj

Required. String object or text.

SubString

Required. The substring to be searched in the String object.

StarIndex

Optional. This integer indicates the index in the String object. If it is omitted, It is searched from the beginning of the string.

Description

The indexOf method returns an integer indicating the starting position of the substring in the String object. If no substring is found,-1 is returned.

If startindex is negative, startindex is treated as zero. If it is larger than the index at the largest character location, it is regarded as the largest possible index.

Search from left to right. Otherwise, this method is the same as lastIndexOf.

Example

The following example illustrates how to use the indexOf method.

 function IndexDemo(str2){   var str1 = "BABEBIBOBUBABEBIBOBU"   var s = str1.indexOf(str2);   return(s);   } 

JavaScript indexOf is case-insensitive.

The indexOf Function Method in JavaScript returns an integer indicating the starting position of the substring in the String object. If no substring is found,-1 is returned. If startindex is negative, startindex is treated as zero. If it is larger than the index at the largest character location, it is regarded as the largest possible index.

The indexOf function performs search from left to right. Otherwise, this method is the same as lastIndexOf.

The following example illustrates how to use the indexOf function method.

functionIndexDemo(str2){  varstr1 = "BABEBIBOBUBABEBIBOBU"  vars = str1.indexOf(str2);  return(s);} 

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