function isTime(str){
var a = str.match(/^(\d{0,2}):(\d{0,2}):(\d{0,2})$/);
if (a == null) return false;
if (a[1]>=24 || a[2]>=60 || a[3]>=60) return false;
return true;
}
function isDateTime(str){
var a = str.match(/^(\d{0,4})-(\d{0,2})-(\d{0,2}) (\d{0,2}):(\d{0,2}):(\d{0,2})$/);
if (a == null) return false;
if ( a[2]>=13 || a[3]>=32 || a[4]>=24 || a[5]>=60 || a[6]>=60) return false;
return true;
}
function isDate(str){
var a = str.match(/^(\d{0,4})-(\d{0,2})-(\d{0,2})$/);
if (a == null) return false;
if ( a[2]>=13 || a[3]>=32 || a[4]>=24) return false;
return true;
}
function validate(obj,type){
var range=obj.createTextRange(); 
var text = range.text;
var selrange = document.selection.createRange();
var seltext = selrange.text;
var startpos = 0,endpos = 0;
while(selrange.compareEndPoints("StartToStart",range)>0){ 
selrange.moveStart("character",-1); 
startpos ++;
}
while(selrange.compareEndPoints("EndToStart",range)>0){ 
selrange.moveEnd("character",-1); 
endpos ++;
}
if(event.keyCode>=48){ 
var keytext = String.fromCharCode(event.keyCode);
text = text.substring(0,startpos) + keytext + text.substring(endpos,text.length);
}else if(event.keyCode == 46){//delete
if(startpos == endpos)text = text.substring(0,startpos) + text.substring

(startpos+1,text.length);
else text = text.substring(0,startpos) + text.substring(endpos,text.length);
}else if(event.keyCode == 8){
if(startpos == endpos)text = text.substring(0,startpos-1) + text.substring

(startpos,text.length);
else text = text.substring(0,startpos) + text.substring(endpos,text.length);
}
if(event.keyCode == 45){
event.returnValue = false;
return;
}
var valid;
switch(type){
case 1:valid = isDate(text);break;
case 2:valid = isTime(text);break;
case 3:valid = isDateTime(text);break;
default:valid = false;
}
if(!valid){
event.returnValue = false;
}
}
//日期验证框：<br><input onkeyDown="validate(this,1)" value="0000-00-00"> <br>

//时间验证框：<br><input onkeyDown="validate(this,2)" value="00:00:00"> <br>

//日期时间验证框：<br><input onkeyDown="validate(this,3)" value="0000-00-00 00:00:00"> <br>