为什么在执行JavaScript脚本是需要点击提交按钮二次


定义部分如下：
<INPUT style="Z-INDEX: 106; LEFT: 417px; WIDTH: 77px; POSITION: absolute; TOP: 23px; HEIGHT: 25px"
onclick="submit1(this.form.rdbtn_WriteCode,this.form.txt_WriteCode,this.form.msg)"
type="button" value="查询">
-----------------------------------------------------------------------------------
执行部分如下：
<script language="javascript">
function submit1(WriteCode,txt_WriteCode,msg)
    {            if (msg.value==3)
            {                
                  if(WriteCode.checked==true)
               {
                        //var s = new Array();
                        s=txt_WriteCode.value;
                        var strlen=s.length;
                        var temps='';
                        var selects='';
                        i=0;
                        //window.alert(s.length);
                        //window.alert(s);
                        //window.alert(s.charAt(1));
                        while(i<strlen)
                       {
                            //window.alert(i);
                            //window.alert(s.charAt(i));
                        if (s.charAt(i)==','||s.charAt(i)==';'||s.charAt(i)=='\t'||s.charAt(i)=='\n')
                        {
                           
                        if (!(temps==''))
                        {
                           selects=selects+","+temps;
                           temps='';
                        }
                        i++;
                         }
                         else
                         {
                            if (s.charAt(i)!='\r'){
                        temps+=s.charAt(i);}
                        i++;
                         }
                        }
                        if (!(temps==''))
                       {
                         selects=selects+","+temps;
                       }
                       selects+='##';
                       s='';
document.frm.hid_P1.value = selects;
              }
            }
            
             //验证
             if(document.frm.hid_P1.value=="" || document.frm.hid_P1.value=="##")
            {
              window.alert("请选择商品!");
              return;
            }