关于JavaScript的问题

Question

<!--现在是字符累加,如果是数字可以用1*varValue来处理,按回车触发累加计算-->
<input type=text onkeydown="if(event.keyCode==13){Result.value=eval('Result.value='+this.value+'+Result.value');this.value='';}"><input type=text id="Result">

Answer 1

用JAVA吧
String str=null;
String str=new StringBuffer(str).append(加入的内容).toSting();

Answer 2

哦，补充更正一下，还要用循环String str=null;
while(……){
   str=new StringBuffer(str).append(加入的内容).toSting();
}

Answer 3

对 gjd111686(数字金刚)做了写简单修改。原理基本上如此，直接用户按提交才提交表单
<input type=text onkeydown="if(event.keyCode==13){Result.value=Result.value+this.value;this.value='';}">
<input type=text id="Result">

Answer 4

这样写出错:
<script language="javascript">    var compositeConditon="";
    var allCondObj=document.getElementById("allCondition");    function doAddCondition(){
      var signObj=document.getElementById("sign");
      var fieldValueObj=document.getElementById("fieldValue");
      var allCondObj=document.getElementById("allCondition");
      allCondObj.value+=signObj.value+fieldValueObj.value;
    }
</script>            <table class=DetailTable>
              <tbody>
                <tr>
                  <td>
                    <select name="sign" size="1">
                    <option value="=">=</option>
                    <option value=">">&gt;</option>
                    <option value=">=">&gt;=</option>
                    <option value="<">&lt;</option>
                    <option value="<=">&lt;=</option>
                    <option value="Like">Like</option>
                    </select>
                  </td>
                  <td><input name="fieldValue" type="text"></td>
                  <td><input name="add" type="button" value="增加" onclick="doAddCondition()"></td>
                  <td><input name="query" type="button" value="查询"></td>
                </tr>
            </table>报错:
'allCondObj'不是对象

Answer 5

这样写出错:
<script language="javascript">    var compositeConditon="";
    var allCondObj=document.getElementById("allCondition");    function doAddCondition(){
      var signObj=document.getElementById("sign");
      var fieldValueObj=document.getElementById("fieldValue");
      allCondObj.value+=signObj.value+fieldValueObj.value;
    }
</script>            <table class=DetailTable>
              <tbody>
                <tr>
                  <td>
                    <select name="sign" size="1">
                    <option value="=">=</option>
                    <option value=">">&gt;</option>
                    <option value=">=">&gt;=</option>
                    <option value="<">&lt;</option>
                    <option value="<=">&lt;=</option>
                    <option value="Like">Like</option>
                    </select>
                  </td>
                  <td><input name="fieldValue" type="text"></td>
                  <td><input name="add" type="button" value="增加" onclick="doAddCondition()"></td>
                  <td><input name="query" type="button" value="查询"></td>
                </tr>
            </table>报错:
'allCondObj'不是对象