JavaScript检查&;单击“提交”按钮时向表中动态添加文本
基本上,我的HTML如下所示:JavaScript检查&;单击“提交”按钮时向表中动态添加文本,javascript,appendchild,createtextnode,Javascript,Appendchild,Createtextnode,基本上,我的HTML如下所示: <form method="post" name="htmlform" onsubmit = "checkFields()"> <table style="width: 479px;" border="30" cellspacing="3" cellpadding="10"> <tbody> <tr> <td valign="top"><span id="firstNameSpan"
<form method="post" name="htmlform" onsubmit = "checkFields()">
<table style="width: 479px;" border="30" cellspacing="3" cellpadding="10">
<tbody>
<tr>
<td valign="top"><span id="firstNameSpan" >First Name *</span></td>
<td valign="top"><input type="text" name="first_name" id="first_name"
size="30" maxlength="50" /></td>
</tr>
<tr>
<td valign="top"><span id = "lastNameSpan" >Last Name *</span></td>
<td valign="top"><input type="text" name="last_name" size="30" maxlength="50"/>
/td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="radio" name="sex"
value="male" /> Male <input type="radio" name="sex"
value="female" /> Female</td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="submit" value="submit"
/></td>
</tr>
</tbody>
</table>
</form>
名字*
姓*
/td>
男女
提交表单时,onsubmit()事件检查first_name textfield是否为空,如果为空,则其左侧的标签或范围将附加到输出“first name*”+“you must enter a first name”,类似地,姓氏和性别也是如此
问题是表中的文本不会随appendchild更新。当我将语句包含在调试警报中时,消息被追加,然后消失
下面是onsubmit=“checkFields()”的JavaScript代码
函数checkFields(){
var firstName=document.getElementById(“first_name”).value;
var lastName=document.getElementById(“姓氏”).value;
如果(firstName==“”){
//请输入一个名字
var nameHint=“请输入名字”;
var node=document.getElementById(“firstNameSpan”);
//警报(node.appendChild(document.createTextNode(nameHint));
//不起作用
appendChild(document.createTextNode(nameHint));
}如果(lastName==“”){
//附加代码
}
}
提前谢谢,非常感谢你的帮助。还有JavaScript调试器吗
问候
David D我相信由于html不正确,您的示例代码无法正常工作
document.getElementById(“姓氏”)
将返回未定义
谢谢大家,我已经掌握了JFiddle的诀窍。虽然错误消息对调试没有帮助,但是分割屏幕非常有用。下面是完整的代码(1)HTML(2)JavaScript
<form method="post" name="htmlform" onsubmit="return checkFields();">
<table style="width: 479px;" border="30" cellspacing="3" cellpadding="10">
<tbody>
<tr>
<td valign="top"><span id="firstNameSpan" >First Name *</span></td>
<td valign="top"><input type="text" name="first_name" id="first_name"
size="30" maxlength="50" /></td>
</tr>
<tr>
<td valign="top"><span id = "lastNameSpan" >Last Name *</span></td>
<td valign="top"><input type="text" name="last_name" id="last_name" size="30"
maxlength="50" /></td>
</tr>
<tr>
<td style="text-align: center;" colspan="2" id = "sexMessage">
Please select Male or Female*</td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="radio"
name="sex" value="male" /> Male <input type="radio" name="sex"
value="female" /> Female</td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="submit" value="submit"
/></td>
</tr>
</tbody>
</table>
</form>
名字*
姓*
请选择男性或女性*
男女
对表单中onsubmit按钮的未填充字段做出反应的JavaScript代码如下:(有没有使代码更简单的方法??)
window.checkFields=function()
{
var firstName=document.getElementById(“first_name”);
var lastName=document.getElementById(“姓氏”);
如果(firstName.value==“”)
{
//请输入一个名字
var nameHint=“*请输入名字”;
var fnNode=document.getElementById(“firstNameSpan”);
while(fnNode.firstChild)
{
fnNode.removeChild(fnNode.firstChild)
}
appendChild(document.createTextNode(nameHint));
fnNode.style.color=“红色”;
}否则{
var nameHint=“First Name*”;
var fnNode=document.getElementById(“firstNameSpan”);
while(fnNode.firstChild)
{
fnNode.removeChild(fnNode.firstChild)
}
appendChild(document.createTextNode(nameHint));
fnNode.style.color=“黑色”;
}
如果(lastName.value==“”)
{
//附加代码
var nameHint=“*请输入姓氏”;
var lnNode=document.getElementById(“lastNameSpan”);
while(lnNode.firstChild)
{
lnNode.removeChild(lnNode.firstChild)
}
appendChild(document.createTextNode(nameHint));
lnNode.style.color=“红色”;
}否则{
var nameHint=“Last Name*”;
var lnNode=document.getElementById(“lastNameSpan”);
while(lnNode.firstChild)
{
lnNode.removeChild(lnNode.firstChild)
}
appendChild(document.createTextNode(nameHint));
lnNode.style.color=“黑色”;
}
var radios=document.getElementsByName(“sex”);
var radioValue=“”
对于(var i=0;iIn附加代码
是否从函数中返回false
?如果要停止表单提交,则需要执行此操作。并删除onsubmit=
中=
周围的空白。您的浏览器有内置的JS调试器。Chrome/Safari在菜单中有开发工具。Firefox有控制台,加上Firebug扩展,IE中的F12打开开发者工具。如果你还没有考虑到它,并且需求允许,你应该研究jQuery来做客户端工作。甚至还有一个验证插件:我编辑了它以删除else语句,因为我希望在响应空或未选择的事件时更改所有3个左侧文本我使用firefox,所以我会调查Firebug
<form method="post" name="htmlform" onsubmit="return checkFields();">
<table style="width: 479px;" border="30" cellspacing="3" cellpadding="10">
<tbody>
<tr>
<td valign="top"><span id="firstNameSpan" >First Name *</span></td>
<td valign="top"><input type="text" name="first_name" id="first_name"
size="30" maxlength="50" /></td>
</tr>
<tr>
<td valign="top"><span id = "lastNameSpan" >Last Name *</span></td>
<td valign="top"><input type="text" name="last_name" id="last_name" size="30"
maxlength="50" /></td>
</tr>
<tr>
<td style="text-align: center;" colspan="2" id = "sexMessage">
Please select Male or Female*</td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="radio"
name="sex" value="male" /> Male <input type="radio" name="sex"
value="female" /> Female</td>
</tr>
<tr>
<td style="text-align: center;" colspan="2"><input type="submit" value="submit"
/></td>
</tr>
</tbody>
</table>
</form>
window.checkFields = function()
{
var firstName = document.getElementById("first_name");
var lastName = document.getElementById("last_name");
if(firstName.value == "")
{
//<span style='color:red'> Please enter a first name </span>
var nameHint = " *Please enter a first name ";
var fnNode = document.getElementById("firstNameSpan");
while(fnNode.firstChild)
{
fnNode.removeChild(fnNode.firstChild)
}
fnNode.appendChild(document.createTextNode(nameHint));
fnNode.style.color="red";
} else{
var nameHint = " First Name *";
var fnNode = document.getElementById("firstNameSpan");
while(fnNode.firstChild)
{
fnNode.removeChild(fnNode.firstChild)
}
fnNode.appendChild(document.createTextNode(nameHint));
fnNode.style.color="black";
}
if (lastName.value == "")
{
//additional code
var nameHint = " *Please enter a last name";
var lnNode = document.getElementById("lastNameSpan");
while(lnNode.firstChild)
{
lnNode.removeChild(lnNode.firstChild)
}
lnNode.appendChild(document.createTextNode(nameHint));
lnNode.style.color="red";
} else{
var nameHint = " Last Name *";
var lnNode = document.getElementById("lastNameSpan");
while(lnNode.firstChild)
{
lnNode.removeChild(lnNode.firstChild)
}
lnNode.appendChild(document.createTextNode(nameHint));
lnNode.style.color="black";
}
var radios = document.getElementsByName("sex");
var radioValue = ""
for(var i=0; i<radios.length; i++)
{
if(radios[i].checked)
{
radioValue = radios[i].value;
}
}
if(radioValue === "")
{
var sexNode = document.getElementById("sexMessage");
var nameHint = "*You did not choose a sex";
while(sexNode.firstChild)
{
sexNode.removeChild(sexNode.firstChild);
}
sexNode.appendChild(document.createTextNode(nameHint));
sexNode.style.color="red";
} else {
var sexNode = document.getElementById("sexMessage");
var nameHint = "Please select Male or Female*";
while(sexNode.firstChild)
{
sexNode.removeChild(sexNode.firstChild);
}
sexNode.appendChild(document.createTextNode(nameHint));
sexNode.style.color="black";
}
return false;
}