In modern page design, JavaSricpt is quit important to do some input check at Client side.
In the comp231 project, we want to build a library management system based on Web, so JavaScript is used
Here I do some summary:
1. check whether the input of a form is Empty or not:
<SCRIPT LANGUAGE="JavaScript">
<!--
{
if(form.name.value.length==0)
alert("input empty");
else
form.submit();
}
//-->
</SCRIPT>
here, form is the name of the <form> and name is the text of pass name, in this check() the situation that all spaces in name can't be detected.
2. check whether the input is a Number or not
<SCRIPT LANGUAGE="JavaScript">
<!--
function check()
{
if(isNaN(aaform.aa.value))
alert("input is not a number");
else
alert("input is a number");
}
//-->
</SCRIPT>
3 check whether a checkbox is checked
<SCRIPT LANGUAGE="JavaScript">
<!--
function checkb()
{
if(myform.mycheckbox.check)
alert("checkd");
else
alert("not checked");
}
//-->
</SCRIPT>