Javascript 当滚动到该节时，将执行函数

我有这些代码，可以在textarea占位符中创建一个键入脚本。它工作得很好。但是当我滚动到表单div时，我需要执行typeIt函数

var txt=“滚动到节时将执行函数”； var修改_txt=“”

---

您需要捕获并为scroll事件分配一个事件处理程序

为了演示的目的，我用一些虚拟数据做了一个div

HTML内容

<div id="scrollDiv" style="width:50px;height:50px;overflow:scroll;" >We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here

We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here</div>

您可以这样使用它（代码库示例）：

1
1.
1.
1.
1.
2.
2.
2.
2.
var oTop=$（'#2'）.offset（）.top-window.innerHeight；
$（窗口）。滚动（函数（）{
var pTop=$（'body'）.scrollTop（）；
console.log（pTop+'-'+oTop）；//仅用于调试
if（pTop>oTop）{
警惕（）；
}
});
功能人性化（）{
返回Math.round（Math.random（）*（200-30））+30；
}
//删除修改后字符串中的最后一个字符
函数删除字符（文本）{
//返回除最后一个字符以外的所有字符
text=text.substring（0，text.length-1）；
返回文本；
}
//插入文字末尾添加的字符
函数addCharacter（文本，添加字符）{
text=文本+添加的字符；
返回文本；
}
//输入错误[char]。错误只是一个自我引用，未使用
变量类型={
}
var超时；
var txtLen=txt.length；
var-char=0；
$（'textarea'）.attr（'placeholder'，'|'）；
函数typeIt（）{
修改的_txt+=txt.charAt（char）；
$（'textarea'）.attr（'placeholder'，modified_txt+'|'）；
if（char==txtLen）{
$（'textarea'）.attr（'placeholder'，$（'textarea'）.attr（'placeholder'）.slice（0，-1））；//删除“|”
return；//文本完全写入后停止循环。
}
var测试=输入错误[char]；
如果（测试！==未定义）{
setTimeout（函数（）{
var chunk_one=测试.校正（修改的_txt）；
modified_txt=chunk_one；
char++；
键入它（）；
}，人性化（））；
}
//如果没有发现拼写错误，则移动到下一个字符
否则{
setTimeout（函数（）{
char++；
键入它（）；
}，人性化（））；
}
}
$（函数（）{
键入它（）；
});//结束jquery

谢谢萨蒂什。我对jquery不太了解。你能给我一个工作示例吗？我试过了，但没有执行。请查看链接。我需要在滚动到表单div时开始键入，你说的starring是什么意思？对不起，它没有开始，它正在启动n#vnuukw当你滚动到div时，它启动了你的函数？它启动了吗？不，它不执行这个功能

<div id="scrollDiv" style="width:50px;height:50px;overflow:scroll;" >We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here

We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here We've Worked For a lot of people and of course we've made them so happy! You can read some handpicked Word about us here</div>

  $('#scrollDiv').scroll(function(){
alert('scrolling');
});

<div>1</div>
<div>1</div>
<div>1</div>
<div>1</div>
<div>1</div>
<div id="2">2</div>
<div>2</div>
<div>2</div>
<div>2</div>

<script>
    var oTop = $('#2').offset().top - window.innerHeight;
    $(window).scroll(function () {

        var pTop = $('body').scrollTop();
        console.log(pTop + ' - ' + oTop);   //just for your debugging
        if (pTop > oTop) {
            alert();
        }
    });

    function humanize() {
        return Math.round(Math.random() * (200 - 30)) + 30;
    }

    //Delete final character in modified string
    function deleteCharacter(text) {
        //return everything but the last character
        text = text.substring(0, text.length - 1);
        return text;
    }

    //Insert character_added at end of text
    function addCharacter(text, character_added) {
        text = text + character_added;
        return text;
    }

    //typos[char].error is just a self reference, it is not used
    var typos = {
    }

    var timeOut;
    var txtLen = txt.length;
    var char = 0;
    $('textarea').attr('placeholder', '|');
    function typeIt() {
        modified_txt += txt.charAt(char);
        $('textarea').attr('placeholder', modified_txt + '|');

        if (char === txtLen) {
            $('textarea').attr('placeholder', $('textarea').attr('placeholder').slice(0, -1)); // remove the '|'
            return; //Stop the loop once text is completely written.
        }

        var test = typos[char];
        if (test !== undefined) {
            setTimeout(function () {
                var chunk_one = test.correction(modified_txt);
                modified_txt = chunk_one;
                char++;
                typeIt();
            }, humanize());
        }
            //If no typos are found then move to the next character
        else {
            setTimeout(function () {
                char++;
                typeIt();
            }, humanize());
        }
    }

    $(function () {
        typeIt();

    });//end jquery
</script>