Examples of indexOf () and lastIndexOf application methods in Javascript, indexoflastindexof

Examples of indexOf () and lastIndexOf application methods in Javascript, indexoflastindexof

IndexOf () method

indexOf() Returns the position of the first occurrence of a specified string value.

Note:indexOf() The method is case sensitive!

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

Use the 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 ('/'); // query alert (str. indexOf ('/', 16); // query alert (str. indexOf ('x'); // If no result is found,-1 is returned;

IndexOf () Method Instance

Var str = 'focus on script learning, share script learning materials and learning skills! '; Var s =' script; // the content to be queried var I = 0; // The first few queries/* 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 where a specified string value appears at the end, and searches for the specified position in a string from the back to the front.

Note:lastIndexOf() The method is case sensitive!

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

LastIndexOf ()Method Instance

Var str = 'focus on Web Front-end learning and share Web Front-end learning materials and learning skills! '; Alert (str. indexOf ('w', 0); // query alert (str. lastIndexOf ('w', 24); // query from the back

If the 2nd values are negative, the default value is 0.

Summary

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