function check() {

	if (document.form_caigou.txtcontact.value==""){
		alert ("请填写您的姓名！");	
		document.form_caigou.txtcontact.focus();
		return false;
	}
	
		if (document.form_caigou.txtmobile.value==""){
		alert ("请填写您的联系电话！");	
		document.form_caigou.txtmobile.focus();
		return false;
	}	
	
		if (document.form_caigou.txtcontent.value==""){
		alert ("	请填写留言内容！");	
		document.form_caigou.txtcontent.focus();
		return false;
	}	
	
		if (document.form_caigou.txtvalidate.value==""){
		alert ("	验证码不能为空！");	
		document.form_caigou.txtvalidate.focus();
		return false;
	}	

	return true;
}