Question

这是我的javascript代码当我第二次按下提交按钮进入另一个网址时发生了什么，但在第一次它给出结果正常可以任何人帮助我PLZ

 function validatenewcat(){
        var category = document.getElementById("cat").value;
        if(category==""){
            setTimeout(document.getElementById("validate").innerHTML="!PLz Enter The Category Name", 2000);
            return false;
        }
    else{
        var url="catnamecheck.do?id="+category;
         xmlhttp.open("post", url,true);
         xmlhttp.send(null);
         xmlhttp.onreadystatechange=function(){
          if(xmlhttp.readyState==4){      
                 if(xmlhttp.status==200){   
                    var temp = xmlhttp.responseText;
                    obj = JSON.parse(temp);
                  if(obj.catgoryname==category) {
                     alert(obj.catgoryname);
                        alert(category);
                         document.getElementById("validate").innerHTML="!PLz Enter The Unique Category Name";
                        return false; 
                     }
                 if(obj.catgoryname!=category){
                    alert("inside true"+obj.catgoryname);
                    alert("inside true"+category);
                       return true; 
                     }
                  }
              }
           }
        }
    }

这是我的java代码，我从ajax

调用此代码

public Map<String, String> catuniqecheck(String id) {
    Connection c = null;
    PreparedStatement ps1 = null;
    ResultSet rs1 = null;
    String sql=null;
    try{
        c = JDBCHelper.getConnection();
        if(c!=null)
        {
            Map<String, String> map = new HashMap<String, String>();
            sql="select * from catgory where catgoryname=?";
            ps1=c.prepareStatement(sql);
            ps1.setString(1, id);
            ps1.execute();
            rs1=ps1.getResultSet();
            if(rs1.next())
            {
                System.out.println("insdide of the catuniqecheck");
                map.put("catgoryname",rs1.getString("catgoryname"));
            }
            return map;
        }   
       else
         {  
               System.out.println("DB connection Established");
               return null  ;
         }
        }
        catch (Exception e) {
            // TODO: handle exception
               return null  ;
        }
finally{
            JDBCHelper.close(rs1);
            JDBCHelper.close(ps1);
            JDBCHelper.close(c);
       }
}

这是我的sevlet代码

if (uri.contains("/catnamecheck.do")) {
        Project p1=new Project();
        String id=request.getParameter("id");
        System.out.println("inside uniq check id"+id);
        Map<String, String> result =p1.catuniqecheck(id);
        if(result!=null)
        {
            System.out.println("inside success");
            JSONObject json = new JSONObject();
            json.accumulateAll(result);
            System.out.println("inside json"+json.toString());
            response.setContentType("application/json");
            response.getWriter().write(json.toString());
        }
        if(result==null)
        {
            System.out.println("inside filure");
        }
    }

这是我的jsp代码

<form name="frm" action="createnewcatgoryBean.jsp" onsubmit="return validatenewcat()" method="post">
<table style="padding: 5px 0px 0px 8px;">
<tr>
<th colspan="2">
<div style="width: width:271px; color:red;" id="validate"></div>
</th>
</tr>
<tr>
<th>Category Name<span>:</span></th><td><input id="cat"  onblur="return validatenewcat()" type="text" name="category">
</td>
</tr>
<tr>
<th>Quotations form<span>:</span></th><td><input type="checkbox" name="quotations"></td>
</tr>
<tr>
<th>Agreement form<span>:</span></th><td><input type="checkbox" name="agreement"></td>
</tr>
<tr>
<th>Payment form<span>:</span></th><td><input type="checkbox" name="payment"></td>
</tr>
<tr>
<th>ETI<span>:</span></th><td><input type="checkbox" name="eti"></td>
</tr>
<tr>
<td colspan="2" style="float:right; padding-top:15px">
<input type="submit" value="Submit"  style="width: 60px;">
</td>
</tr>
</table>
</form>

Answer 1

您已设置表单action="createnewcatgoryBean.jsp"。如果验证成功，它将提交到此页面。为避免提交，请从您的javascript返回false。

else {
    var url = "catnamecheck.do?id=" + category;
    xmlhttp.open("post", url, true);
    xmlhttp.send(null);
    xmlhttp.onreadystatechange = function () {
        if (xmlhttp.readyState == 4) {
            if (xmlhttp.status == 200) {
                var temp = xmlhttp.responseText;
                obj = JSON.parse(temp);
                if (obj.catgoryname == category) {
                    alert(obj.catgoryname);
                    alert(category);
                    document.getElementById("validate").innerHTML = "!PLz Enter The Unique Category Name";
                    return false;
                }
                if (obj.catgoryname != category) {
                    alert("inside true" + obj.catgoryname);
                    alert("inside true" + category);
                    return true;
                }
            }
        }
    }

    return false; //return false to avoid form submission
}

如果我按下提交按钮，进入servlet中的另一个URL

1 个答案: