Javascript函数没有'；t正常运行并显示一个框仅1秒

我的javascript函数有问题。当用户点击“szukaj”按钮时，它应该为用户显示一个框。它运行，但只运行大约1秒

HTML代码

<p id = "paragraph">                                 <!--search box-->
    <input type = "text" name = "serachBar"/>
    <input type = "button" value = "szukaj" name = "search"/>
</p>
<div id = "searchImage">                             <!--search button style-->
    <a href = "" onclick = "popUp('paragraph')" >
        <img src = "images/searchButton.jpg"/>
    </a>
</div>

javascript本身

function popUp(menu){
    var box = document.getElementById(menu);

    if(!box || box.style.display == "block"){
        box.style.display = "none";
    }
    else {
        box.style.display = "block";        
    }       
}

用HTML试试这个

<p id = "paragraph">                                 <!--search box-->
  <input type = "text" name = "serachBar"/>
  <input type = "button" value = "szukaj" name = "search"/>
</p>
<div id = "searchImage">                             <!--search button style-->
 <a href = "#" onclick = "popUp('paragraph')" >
  <img src = "images/searchButton.jpg"/>
 </a>
</div>

在

如果你还想使用
哦，是的，我一定是瞎了眼什么的。Thanx很多。你的javascript有点不好的逻辑。如果（！box）短路，则box.style.display将在null或undefined上调用，这将引发异常。最好在所有显示逻辑周围调用if（box）{…}。
<p id = "paragraph">                                 <!--search box-->
  <input type = "text" name = "serachBar"/>
  <input type = "button" value = "szukaj" name = "search"/>
</p>
<div id = "searchImage">                             <!--search button style-->
 <a href = "#" onclick = "popUp('paragraph')" >
  <img src = "images/searchButton.jpg"/>
 </a>
</div>

<p id = "paragraph"> <!--search box-->
    <input type = "text" name = "serachBar"/>
    <input type = "button" value = "szukaj" name = "search"/>
</p>
<div id = "searchImage"> <!--search button style-->
    <div onclick = "popUp('paragraph')" >
        <img src = "images/searchButton.jpg"/>
    </div>
</div>

function popUp(menu){
    event.preventDefault(); // if using an <a> tag
    var box = document.getElementById(menu);
    if (box) {
        if (box.style.display === "block") {
            box.style.display = "none";
        }
        else {
            box.style.display = "block";        
        }       
    }
}