method one:
var oLi = document.querySelector("li"); for(var i=0; i<oLis.length; i++){ oLis[i].onclick = (function(j){ return function(){ alert(j); } })(i); }
Method Two:
var oLi = document.querySelector("li")； for(var i=0; i<oLi.length; i++){ (function(j){ oLi[j].onclick = function(){ alert(j); }; })(i); }
Method three:
var oLi = document.getElementsByTagName('li'); function func(obj,i){ obj.onclick = function(){ alert (i); } } for(var i = 0; i<oLi.length; i++){ func(oLi[i], i); }
Method four:
var oLi = document.getElementsByTagName('li'); for(var i=0; i<oLi.length; i++){ oLi[i].setAttribute("onclick", "alert("+i+");"); }
Method five:
for(var i=0; i<oLi.length; i++){ oLi[i].index = i; oLi[i].onclick = function(){ alert(this.index); } }
Method six:
<body> <input type="button" value="按钮1"> <input type="button" value="按钮2"> <input type="button" value="按钮3"> <script type="text/javascript"> var btns = document.getElementsByTagName("input"); for (let i = 0; i < 3; i++) { btns [I] .onclick = function () { the console.log ( " I was the first " + (I) + " buttons " ); }; } </ Script > </ body >