JavaScript indexof () and LastIndexOf application Method Instance _ basics

IndexOf () method

indexOf() method returns the position of the first occurrence of a specified string value in a string.

Note: indexOf() methods are sensitive to case sensitivity!

Note: If the string value to retrieve does not appear, the method returns-1.

Using the previous charat () method

var str = ' www.webclks.com/archives/3309 ';
for (var i=0 i<str.length; i++) {
 if (Str.charat (i) = = '/') {
 alert (i);
 }
}

IndexOf () method

var str = ' www.webclks.com/archives/3309 ';
Alert (Str.indexof ('/')); Check alert from the No. 0 (
str.indexof ('/', 16));//check alert from 16th
(str.indexof (' x '));/no return-1;

IndexOf () Method instance

var str= ' Focus on scripting, sharing script learning materials and learning tips! ';
var s= ' script; The content to query
var i=0//From the start query/
* for
(; Str.indexof (s,i)!=-1;) {
 alert (Str.indexof (s,i));
 I=str.indexof (s,i) +s.length;
}
*/While


(Str.indexof (s,i)!=-1) {
 alert (Str.indexof (s,i));
 I=str.indexof (s,i) +s.length; 
}

LastIndexOf () method

lastIndexOf() method returns the position of the last occurrence of a specified string value, which is searched forward at the specified position in a string.

Note: lastIndexOf() methods are sensitive to case sensitivity!

Note: If the string value to retrieve does not appear, the method returns-1.

LastIndexOf () Method Instance

var str= ' focuses on Web front-end learning, sharing Web front-end learning materials and learning tips! ';
Alert (Str.indexof (' W ', 0)); Look back at
alert (str.lastindexof (' W ', 24));

If the 2nd value is a negative number, the default is 0来 processing

Summarize

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