空输入字段的JavaScript验证
问候，我有这个输入字段， <input name="question"/>我想在单击提交按钮时调用IsEmpty函数。
我尝试了下面的代码，但是没有用。有什么建议吗？
<html>
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=unicode" />
<meta content="CoffeeCup HTML Editor (www.coffeecup.com)" name="generator" />
</head>
<body>
<script language="Javascript">
function IsEmpty() {
if (document.form.question.value == "") {
alert("empty");
}
return;
}
</script>
Question: <input name="question" /> <br/>
<input id="insert" onclick="IsEmpty();" type="submit" value="Add Question" />
</body>
</html>
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3回答
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慕桂英4014372
<script type="text/javascript"> function validateForm() { var a = document.forms["Form"]["answer_a"].value; var b = document.forms["Form"]["answer_b"].value; var c = document.forms["Form"]["answer_c"].value; var d = document.forms["Form"]["answer_d"].value; if (a == null || a == "", b == null || b == "", c == null || c == "", d == null || d == "") { alert("Please Fill All Required Field"); return false; } }</script><form method="post" name="Form" onsubmit="return validateForm()" action=""> <textarea cols="30" rows="2" name="answer_a" id="a"></textarea> <textarea cols="30" rows="2" name="answer_b" id="b"></textarea> <textarea cols="30" rows="2" name="answer_c" id="c"></textarea> <textarea cols="30" rows="2" name="answer_d" id="d"></textarea></form> -
慕村9548890
您缺少必填<form>元素。您的代码应如下所示：function IsEmpty() { if (document.forms['frm'].question.value === "") { alert("empty"); return false; } return true;}<form name="frm"> Question: <input name="question" /> <br /> <input id="insert" onclick="return IsEmpty();" type="submit" value="Add Question" /></form> -
蓝山帝景
输入字段可以包含空格，您要防止这种情况：function isEmpty(str){ return !str.replace(/\s+/, '').length;}例：function isEmpty(str){ return !str.replace(/\s+/, '').length;}document.getElementById("name").addEventListener("input", function() { if( isEmpty(this.value) ) { console.log( "NAME IS EMPTY!" ) }});<input id="name" type="text">
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JavaScript