JS in built-in objects

JavaScript charAt () function String.charat (n)--Returns the character of the specified position (n)

• Char is the abbreviation for character, Chinese "symbol, character"
• Citation URL: http://www.dreamdu.com/javascript/string.charAt/

Charat function syntax

String.charat (n);

Charat function parameters

• N-the position of the character in the string (the position of the first character of the string is 0)

Charat function return value

• Returns the character of n position

• If n is not between 0 and String.length-1, an empty string is returned
• JavaScript indexOf () function string.indexof (substring, startpos)--Returns the position of substring in string
  • Index, Chinese "indexed"
  • Citation URL: http://www.dreamdu.com/javascript/string.indexOf/
  indexof function syntax

  String.IndexOf (substring, startpos);

  indexof function parameters
  • SUBSTRING--substring to find
  • Startpos--optional parameter, starting from the startpos position of string to find substring, if no this parameter will be found from the beginning of the string
  indexof function return value
  • Returns the position of a substring substring in a string
  • No substring found in string substring, return-1
  • JavaScript lastIndexOf () function string.lastindexof (substring, startpos)--Returns the position where the substring last matched (appeared) in a string
    • Last, Chinese "final, end"
    • Citation URL: http://www.dreamdu.com/javascript/string.lastIndexOf/
    LastIndexOf function syntax

    String.LastIndexOf (substring, startpos);
    
    

    LastIndexOf function parameters
    • SUBSTRING--substring to find
    • Startpos--optional parameter, starting from the startpos position of string to find substring, if no this parameter will be found from the beginning of the string
    LastIndexOf function return value
    • Returns the position of the substring substring the last match in a string
    • No substring found in string substring, return-1

    
    JavaScript substring () function string.substring (startpos, Endpos)--Returns a string from the startpos position of string to the Endpos position
         
         
    
          
          
     
           
    substring, Chinese "substring"
     
           
    Citation URL: http://www.dreamdu.com/javascript/string.substring/
     
          
         
         
    substring function syntax
    String.substring (Startpos, endpos);
    
    substring function parameters
         
         
    
          
          
     
           
    Startpos--Start position
     
           
    Endpos--End position
     
          
         
         
    substring function return value
    String
    JavaScript substr () function string.substr (startpos, length)--Returns a string of length from the startpos position of the string
         
         
    
          
          
     
           
    does not conform to the ECMA standard and is not in favor of use.
     
           
    substr, Chinese "substring"
     
           
    Citation URL: http://www.dreamdu.com/javascript/string.substr/
     
          
         
         
    substr function syntax
    String.substr (startpos, length);
    
    substr function parameters
         
         
    
          
          
     
           
    Startpos--Start position (calculated from the end of the string when negative numbers are taken)
     
           
    Length--Lengths
     
          
         
         
    substr function return value
    String
    JavaScript toLowerCase () function string.tolowercase ()--Returns a lowercase string
         
         
    
          
          
     
           
    lowercase, chinese "lowercase"
     
           
    Citation URL: http://www.dreamdu.com/javascript/string.toLowerCase/
     
          
         
         
    toLowerCase function syntax
    String.tolowercase ();
    
    toLowerCase function return value
    Returns a lowercase string
    JavaScript touppercase () function string.touppercase ()--Returns an uppercase string
         
         
    
          
          
     
           
    uppercase, Chinese "uppercase"
     
           
    Citation URL: http://www.dreamdu.com/javascript/string.toUpperCase/
     
          
         
         
    toUpperCase function syntax
    String.touppercase ();
    
    toUpperCase function return value
    Uppercase string
    toUpperCase Function Example
    var str = "www.dreamdu.com";d Ocument.write (Str.touppercase ());
    
    Results:
    WWW.DREAMDU.COM
    
    

  
  

JS in built-in objects