//--检测搜索的安全性-->

	   function doSearch() {

	      var keywords = trim(document.searchForm.keywords.value);
		 // var direction = document.searchForm.direction.value;

          if(keywords == ""||keywords.substring(0,3)=="请输入") {
		    alert("请输入关键字！");
			document.searchForm.keywords.focus();
		    return false;
		  }  
		  
		 }

           function trim(inputString) {
	   
              if (typeof inputString != "string") { return inputString; }
              var retValue = inputString;
              var ch = retValue.substring(0, 1);
              while (ch == " ") { 
	          //检查字符串开始部分的空格
                  retValue = retValue.substring(1, retValue.length);
                  ch = retValue.substring(0, 1);
              }
              ch = retValue.substring(retValue.length-1, retValue.length);
              while (ch == " ") {
                 //检查字符串结束部分的空格
                 retValue = retValue.substring(0, retValue.length-1);
                 ch = retValue.substring(retValue.length-1, retValue.length);
              }
              while (retValue.indexOf("  ") != -1) { 
	         //将文字中间多个相连的空格变为一个空格
                 retValue = retValue.substring(0, retValue.indexOf("  ")) + retValue.substring(retValue.indexOf("  ")+1, retValue.length); 
              }
              return retValue;
           } 
          //搜索时候显示与隐藏菜单--更改菜单的样式
           function g4(o){return document.getElementById(o);} 
            function QoverLi4(n){ 
            for(var i=1;i<=5;i++){g4('tb4_'+i).className='normaltab4';}
            g4('tb4_'+n).className='hovertab4'; 
            var resultvalue;
            var whichvalue;
            switch(n){
              case 1:
                    resultvalue="请输入供应关键字";
                    whichvalue="sale";
                    break;
              case 2:
                    resultvalue="请输入求购关键字";
                    whichvalue="buy";
                    break;
              case 3:
                    resultvalue="请输入资讯关键字";
                    whichvalue="news";
                    break;
              case 4:
                     resultvalue="请输入企业关键字";
                     whichvalue="corporation";
                     break;
              default:
                    resultvalue="请输入招商关键字";
                    whichvalue="zhaoshang";
                    break;
            }
            if(document.searchForm.hd.value==""){
            document.searchForm.keywords.value=resultvalue;
            }else if(document.searchForm.keywords.value.substring(0,3)=="请输入"){
              document.searchForm.keywords.value=document.searchForm.hd.value;
             }else if(document.searchForm.keywords.value==""){
             document.searchForm.keywords.value=document.searchForm.hd.value;
            }else if(document.searchForm.keywords.value!=document.searchForm.hd.value){
              document.searchForm.hd.value=document.searchForm.keywords.value;
              document.searchForm.keywords.value=document.searchForm.keywords.value;
            }
            g4("wh").value=whichvalue;
            
            }

//-->