{var%20f='http://v.t.sina.com.cn/share/share.php?appkey=1515056452',u=z||d.location,p=['&url=',e(u),'&title=',e(t||d.title),'&source=',e(r),'&sourceUrl=',e(l),'&content=',c||'gb2312','&pic=',e(p||'')].join('');function%20a(){if(!window.open([f,p].join(''),'mb',['toolbar=0,status=0,resizable=1,width=440,height=430,left=',(s.width-440)/2,',top=',(s.height-430)/2].join('')))u.href=[f,p].join('');};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();})(screen,document,encodeURIComponent,'','','https://www.manongdao.com/data/attach/logo/logo.png', '推荐 虎瘦雄心在 的问题《How to set a min and max character length on a HTM》','https://www.manongdao.com/q-746888.html','页面编码gb2312|utf-8默认gb2312'));){kind=link}
I am only GCSE level and I need a text box in my code to only have 4 characters. I have made it a max of 4 but I need it to have a minimum of 4 aswell. I also made it only accept numbers. I am not using HTML 5 at my school.
This is my whole code:
<head>
<title>Exam entry</title>
<script language="javascript" type="text/javascript">
function validateForm() {
var result = true;
var msg="";
if (document.ExamEntry.name.value=="") {
msg+="You must enter your name \n";
document.ExamEntry.name.focus();
document.getElementById('name').style.color="red";
result = false;
}
if (document.ExamEntry.subject.value=="") {
msg+="You must enter the subject. \n";
document.ExamEntry.subject.focus();
document.getElementById('subject').style.color="red";
result = false;
}
if (document.ExamEntry.ExamNumber.value=="") {
msg+="You must enter your exam number. \n";
document.ExamEntry.ExamNumber.focus();
document.getElementById('ExamNumber').style.color="red";
result = false;
}
if(document.ExamEntry.ExamNoLen.value.length <4) {
msg+="Your eaxm nuber must be 4 digits long. \n";
document.ExamEntry.ExamNumber.focus();
document.getElementById('ExamNumber').style.color="red";
result = false;
}
checkInput(elem){
if(elem.value.length != 4){
alert("This value needs to be 4 characters long!");
elem.value = ""; // Reset the textbox
}
else{
alert("This value is 4 characters long.");
}
}
if(msg==""){
return result;
}
{
alert(msg)
return result;
}
}
</script>
</head>
<body>
<h1>Exam Entry Form</h1>
<form name="ExamEntry" method="post" action="success.html">
<table width="50%" border="0">
<tr>
<td id="name">Name</td>
<td><input type="text" name="name" /></td>
</tr>
<tr>
<td id="subject">Subject</td>
<td><input type="text" name="subject" /></td>
</tr>
<tr>
<td id="ExamNumber">Exam Number </td>
<td>
<input name="ExamNumber" type="text"
onkeydown="return ( event.ctrlKey || event.altKey
|| (47<event.keyCode && event.keyCode<58 && event.shiftKey==false)
|| (95<event.keyCode && event.keyCode<106)
|| (event.keyCode==8) || (event.keyCode==9)
|| (event.keyCode>34 && event.keyCode<40)
|| (event.keyCode==46) )"
maxlength="4" onblur="checkInput(this)" />
</td>
</tr>
<tr>
<td><input type="submit" name="Submit" value="Submit" onClick="return validateForm();" /></td>
<td><input type="reset" name="Reset" value="Reset" /></td>
</tr>
</table>
</form>
</body>
Well you can't have a minlength because your users are going to need to type 1,2 and 3 characters to get to 4. (Unless you apply some sort of input mask which is more advanced). But you can check that it is 4 characters long when it is blurred..
And then a simple JavaScript function..