JS表单验证集锦(之一)
JS代码判断集锦(之一) ~~~~~~~~~~~~~~~~~~


<script language="JavaScript">
function checkid(iden,year,month,day){

if (iden.value.length==15) {


if ((iden.value.lastIndexOf(month.value+day.value))==8) {

return true;
}
return false;
}
if (iden.value.length==18) {


if ((iden.value.indexOf(year.value+month.value+day.value))==6) {

return true;
}
return false;
}

return false;
}


function isCharsInBag (s, bag)
{
var i;
for (i = 0; i < s.length; i++)
{
var c = s.charAt(i);
if (bag.indexOf(c) == -1) return false;
}
return true;
}
function isEmpty(s)
{
return ((s == null) || (s.length == 0))
}

function isWhitespace (s)
{
var whitespace = " \t\n\r";
var i;
for (i = 0; i < s.length; i++)
{
var c = s.charAt(i);
if (whitespace.indexOf(c) >= 0)
{
return true;
}
}
return false;
}
function isEmail (s,t)
{
if (isEmpty(s))
{
window.alert("输入的E-mail地址不能为空，请输入！");
mobj = eval(t);
mobj.focus();
mobj.select();
return false
}
if (isWhitespace(s))
{
window.alert("输入的E-mail地址中不能包含空格符，请重新输入！");
mobj = eval(t)
mobj.focus()
mobj.select()
return false;
}
var i = 1;
var len = s.length;

if (len > 50)
{
window.alert("email地址长度不能超过50位!");
mobj = eval(t)
mobj.focus()
mobj.select()
return false;
}

pos1 = s.indexOf("@");
pos2 = s.indexOf(".");
pos3 = s.lastIndexOf("@");
pos4 = s.lastIndexOf(".");
if ((pos1 <= 0)||(pos1 == len)||(pos2 <= 0)||(pos2 == len))
{
window.alert("请输入有效的E-mail地址！");
mobj = eval(t)
mobj.focus()
mobj.select()
return false;
}
else
{
if( (pos1 == pos2 - 1) || (pos1 == pos2 + 1)
|| ( pos1 != pos3 )
|| ( pos4 < pos3 ) )
{
window.alert("请输入有效的E-mail地址！");
mobj = eval(t)
mobj.focus()
mobj.select()
return false;
}
}

if ( !isCharsInBag( s, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-_@"))
{
window.alert("email地址中只能包含字符ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.-_@\n" + "请重新输入" );
mobj = eval(t)
mobj.focus()
return false;
}
return true;
}
function isnumber(str){
var digits="1234567890";
var i=0;
var strlen=str.length;
while((i<strlen)){
var char=str.charAt(i);
if(digits.indexOf(char)==-1)return false;i++;
}
return true;
}
function isnumbercode(str){
var digits="1234567890-/";
var i=0;
var strlen=str.length;
while((i<strlen)){
var char=str.charAt(i);
if(digits.indexOf(char)==-1)return false;i++;
}
return true;
}
</script>

<script language=javascript>
function checkForm(theform){
if (document.frm.companyname.value.length==0){
alert("单位名称不能为空。");
mobj = eval("document.frm.companyname");
mobj.focus()
mobj.select()
return false;
}

if (document.frm.address.value.length==0){
alert("单位地址不能为空");
mobj = eval("document.frm.address");
mobj.focus()
mobj.select()
return false;
}

if (document.frm.invest.value.length==0){
alert("投资额不能为空");
mobj = eval("document.frm.invest");
mobj.focus()
mobj.select()
return false;
}
if (document.frm.codeornumber.value.length==0){
alert("法人代码证书号或营业执照编号不能为空");
mobj = eval("document.frm.codeornumber");
mobj.focus()
mobj.select()
return false;
}

if (document.frm.linkman.value.length==0){
alert("联系人不能为空");
mobj = eval("document.frm.linkman");<