计算click（）函数的使用次数

Question

我想知道click（）函数被使用了多少次并记录了但是我总是得到名为“undefined”或“NaN”的错误

 var sleep = 1000; var run = setInterval(function() { var span = document.getElementsByTagName("span"); for (var i = 0; i < span.length; i++) { if (span[i].textContent != "danger") { var jump = document.getElementsByClassName("jump")[0].click(); console.log(jump++); } else { clearInterval(run); } } }, sleep); 

 <span>Danger</span> <button type="button" class="jump">Click</button> 

Answer 1

您需要定义跳转而不是为其分配按钮
另外，我建议使用querySelector（All）而不是getElementsByClass / TagName

 var sleep = 1000, jump=0, jumpBut = document.querySelector(".jump"); var run = setInterval(function() { // move this var outside the loop if the spans never change in number var span = document.querySelectorAll("span"); for (var i = 0; i < span.length; i++) { if (span[i].textContent != "danger") { jumpBut.click(); console.log(jump++); } else { clearInterval(run); } } }, sleep); 

 <span>Danger</span> <button type="button" class="jump">Click</button> 

但请尝试这样做 - 向按钮添加一个click事件监听器并将其添加到计数器中

 var sleep = 1000, jump=0, jumpBut=document.querySelector(".jump"); jumpBut.addEventListener("click",function() { jump++, console.log(jump) }) var run = setInterval(function() { var span = document.querySelectorAll("span"); for (var i = 0; i < span.length; i++) { if (span[i].textContent != "danger") { jumpBut.click(); } else { clearInterval(run); } } }, sleep); 

 <span>Danger</span> <button type="button" class="jump">Click</button> 

Answer 2

你需要一个计数器变量！ 此外，每次调用间隔时都不必使用getElementsByTagName ，除非DOM元素不断变化。

var sleep = 1000;
var counter = 0;
var spans = document.getElementsByTagName("span");
var jump = document.getElementsByClassName("jump")[0];

var run = setInterval(function(){        
    for (var i =0; i< spans.length; i++) {
        if (spans[i].textContent != "danger") {
            jump.click();
            counter++;
            console.log(counter);
       } else {
            clearInterval(run);
       }
    }
}, sleep);