function compareDate( startDate,endDate )
{
//验证开始日期不能大于结束日期,验证条件成立返回真,否则为假
//任何一个输入如果为空,则返回为真
//本比较函数不对填写日期的合法性进行校验,比较日期前应先行
//保证填写的日期为合法的格式,如"2004-1-5"或"2004-01-05"
if ( startDate.value == "" )
return true;
if ( endDate.value == "" )
return true;
var first = startDate.value.indexOf("-");
var last = startDate.value.lastIndexOf("-");
var mLength = last - first -1;
var dLength = startDate.value.length - last-1;
var y = startDate.value.substr( 0, 4 );
var m = startDate.value.substr( 5, mLength );
var d = startDate.value.substr( last + 1, dLength );
var newdate = new Date( y, m-1, d );
var first2 = endDate.value.indexOf("-");
var last2 = endDate.value.lastIndexOf("-");
var mLength2 = last2 - first2 -1;
var dLength2 = endDate.value.length - last2-1;
var y2 = endDate.value.substr( 0, 4 );
var m2 = endDate.value.substr( 5, mLength2 );
var d2 = endDate.value.substr( last2 + 1, dLength2 );
var newdate2 = new Date( y2, m2-1, d2 );