function checkinfo(){
	if (document.sendmail.name.value == "") {
   		alert("用户名不能为空！");
		document.sendmail.name.focus();
		return false;
	}

	if (document.sendmail.tel.value == "") {
	    alert("联系电话不能为空！");
		document.sendmail.tel.focus();
		return false;
	}
	if (isNaN(document.sendmail.tel.value)) {
		alert("联系电话应为数字！");
		document.sendmail.tel.focus();
		return false;
	}
	
	if (document.sendmail.email.value == "") {
 	   alert("Email地址不能为空！");
	   document.sendmail.email.focus();
	   return false;
	}

	if (document.sendmail.email.value.indexOf("@",0) == -1) {
 	   alert("Email地址不合法，请重新输入！");
	   document.sendmail.email.focus();
	   return false;
	}

	if (document.sendmail.email.value.indexOf(".",0) == -1) {
 	   alert("Email地址不合法，请重新输入！");
	   document.sendmail.email.focus();
	   return false;
	}

	if (document.sendmail.content.value == ""){
		alert("内容不能为空！");
		document.sendmail.content.focus();
		return false;
	}
}