Question

<html>
<head>
<script>
function testing(){
    var search1 = document.forms['tfnewsearch']['search1'].value;
    if(search1 == null || search1 == "")
    {   
        alert("Error! Please type in something");
        isValid = false;
    }
}

</script>
</head>
<form name= id="tfnewsearch" method="post" action="" onsubmit ="return testing();">
               <p><input type="text" class="tftextinput" id="search1" size="21" maxlength="120"/>
               <input type="submit" value="search" class="tfbutton"/></p>
</form>
<body>
</body>
</html>

所以我试图在这里做的是，如果用户没有输入任何相当于空值的东西，但是我不明白为什么它不显示弹出窗口，则显示警告弹出窗口。我认为我的功能没有错误，

Answer 1

http://jsfiddle.net/gYg7r/

以下是：

JS：

function testing(){
    var search1 = document.getElementById('search1').value; 

    if(search1 == undefined || search1 == ""){   
        alert("Error! Please type in something");
        isValid = false;
    }
}

HTML：

<form name="searchForm" id="tfnewsearch" method="post" action="http://google.com" onsubmit ="testing();">
    <p><input type="text" class="tftextinput" id="search1" size="21" maxlength="120"/>
    <input type="submit" value="search" class="tfbutton"/></p>
</form>

提醒javascript无法正常工作

1 个答案: