function initbodys(){ $(form('bookid')).change(function(){ var val = this.value,txt=''; if(val!=''){ txt = this.options[this.selectedIndex].text; } form('bookname').value=txt; }); } function changesubmit(d){ if(d.yjdt<=d.jydt)return '预计归还必须大于借阅日期'; }