使用select添加数据出错。
function   Button1_onclick()   { 
 alert(ListBox1.item[ "a "].text); 
 }   
 ListBox1的代码: 
  <select   size= "4 "   name= "ListBox1 "   id= "ListBox1 "   style= "width:   151px "   >  
 		 <option   value= "a "> a </option>  
 		 <option   value= "b "> b </option>  
 		 <option   value= "c "> c </option>  
 	 </select>    
 button的代码。 
  <input   id= "Button1 "   type= "button "   value= "button "   language= "javascript "   onclick= "return   Button1_onclick() "   />    
 报错信息是: 
  'ListBox1.item.a.text '为空或不是对象 
 我将alert(ListBox1.item[ "a "].text);改成: 
 ListBox1.add( "F "); 
 报错:类型不匹配,错误代码为0; 
 请问要执行select如下功能要怎么做: 
 1:添加一行文本 
 2:查找一行文本跟指定的文本是否匹配(想sql语句中的   FieldName   like    '%FieldValue% '). 
 3:删除一条数据。 
------解决方案--------------------一个脚本循环就成啊
------解决方案-------------------- <!DOCTYPE HTML PUBLIC  "-//W3C//DTD HTML 4.0 Transitional//EN ">  
  <html>  
  <head>  
  <title>  New Document  </title>  
  <meta name= "Generator " content= "EditPlus ">  
  <meta name= "Author " content= " ">  
  <meta name= "Keywords " content= " ">  
  <meta name= "Description " content= " ">    
  </head>    
  <body>  
  <script language= "javascript ">  
 	function getPos(serC) 
 	{ 
 		if (serC==null || !serC) 
 		{ 
 			return -1; 
 		} 
 		var objlist=document.getElementById( "test "); 
 		for (var i=0;i <objlist.options.length;i++ ) 
 		{  			 
 			if(objlist.options[i].text.indexOf(serC)> =0) 
 			{ 
 				return i; 
 				break; 
 			} 
 		} 
 		return -1; 
 	} 
  </script>  
  <input type= "text " id= "txt " value= " " />   <input type= "button " onclick= "alert(getPos(txt.value)); " value= "go " />  
  <select id= "test ">  
 	 <option value= "dd "> a </option>  
 	 <option value= "dd "> b </option>  
 	 <option value= "dd "> c </option>  
 	 <option value= "dd "> d </option>  
 	 <option value= "dd "> ef </option>  
 	 <option value= "dd "> dfa </option>  
 	 <option value= "dd "> 测 </option>  
 	 <option value= "dd "> 量 </option>  
 	 <option value= "dd "> 大 </option>  
  </select>  
  </body>  
  </html>