function changeParam(string_param,value){
var arr_param=string_param.split('|'); //param có dang param_a|param_b|...
var arr_value=value.split('|');			//value có dang value_a|value_b|...
var last_url=location.href.replace('#','');


for(i=0;i<arr_param.length;i++){
	//alert(arr_param[i]+" = " +arr_value[i]);
	param=arr_param[i]+'=';//truong hop chua co param nao trong url
	url=last_url;
	index=url.indexOf('&'+param); // truong hop co nhieu param
	if(index<0){
		index=url.indexOf(param);// truong hop co mot minh no
		if (index>0) 
		 url=url.replace(param,'');//bo param di. nhung van con lai gia tri
	}else{
		url=url.replace('&'+param,'');//bo param di. nhung van con lai gia tri
	}
	
	if (index>0){
		pre_param= url.substring(0,index);
		url=url.replace(pre_param,'');//cat bo doan truoc
		//alert(url);
		after_param='';
		next_index=url.indexOf('&');
		if(next_index>=0)
			after_param=url.substring(next_index,url.length);
		//hoan toan loai bo duoc param=value ra khoi url string
		url=pre_param+after_param;
	}
	//else//chưa có para value th2i chi them vao ma thoi
	if(url.indexOf("?")>0)//co it nhat 1 param
		last_url=url + "&"+param+arr_value[i];
	else
		last_url=url +  "?"+param+arr_value[i];
			//alert(pre_param+after_param);
	
}
	location.href = last_url;
	
		

}