<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>Document</title> <style type="text/css"> p{ width: 60px; height: 60px; float: left; margin-right: 20px; background-color: yellowgreen; } </style> </head> <body> <p></p> <p></p> <p></p> <p></p> <p></p> <p></P > < P > </ P > < Script type = "text / JavaScript" > var PS = document.getElementsByTagName ( " P " ); // first, IIFE // for (var I = 0; I <PS .length; i ++) { // (function (m) { // PS [m] .onclick = function () { // Alert ( "I'm old" + m + "point me doing !!?"); // } // }) (I); // } // described second method, is very clever, simple than the first for ( var I= 0 ; i < ps.length; i ++ ) { PS [i] .index = i; // first number everyone convention called index, will do what is in fact called // then set the monitor ps [i] .onclick = function () { Alert ( " I'm old " + the this .index + " point I doing? !! " ) } } </ Script > </ body > </ HTML >