これで私のメソッドの準備が整いました..stackoverflowの助けを借りて:   
  function validatedate(inputText)  
{ 
var thsid=$(inputText).attr('id');
var classname=$(inputText).attr('class');
   var classstr=classname.split(" ");
var ret=true;
var dateformat = /^(0?[1-9]|1[012])[\/\-](0?[1-9]|[12][0-9]|3[01])[\/\-]\d{4}$/;  
// Match the date format through regular expression  
if(inputText.value.trim()!="")
{
if( inputText.value.trim().match(dateformat))  
 {  
  // document.form1.text1.focus();  
   //Test which seperator is used '/' or '-'  
   var opera1 = inputText.value.split('/');  
   var opera2 = inputText.value.split('-');  
  lopera1 = opera1.length;  
 lopera2 = opera2.length;  
  // Extract the string into month, date and year  
   if (lopera1>1)  
    {  
  var pdate = inputText.value.split('/');  
  }  
  else if (lopera2>1)  
  {  
  var pdate = inputText.value.split('-');  
  }  
 var mm  = parseInt(pdate[0]);  
 var dd = parseInt(pdate[1]);  
 var yy = parseInt(pdate[2]);  
  // Create list of days of a month [assume there is no leap year by default]  
   var ListofDays = [31,28,31,30,31,30,31,31,30,31,30,31];  
  if (mm==1 || mm>2)  
  {  
  if (dd>ListofDays[mm-1])  
  {  
  alert('Invalid date format!');
 $(inputText).focus();
  inputText.value="";
   ret=false;
  return false;  
  }  
 }  
 if (mm==2)  
  {  
 var lyear = false;  
 if ( (!(yy % 4) && yy % 100) || !(yy % 400))   
  {  
 lyear = true;  
 }  
 if ((lyear==false) && (dd>=29))  
  {  
  alert('Invalid date format!'); 
  $('#'+thsid).focus();
   inputText.value="";
   ret=false;
  return false;  
 }  
 if ((lyear==true) && (dd>29))  
 {  
 alert('Invalid date format!');  
         $('#'+thsid).focus();
 inputText.value="";
  ret=false;
   return false;  
 }  
  }  
  }  
  else  
   {  
   alert("Invalid date format!");  
    $('#'+thsid).focus();
 inputText.value="";
    ret=false;
  return false;  
       }
 }