Jquery禁止输入

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">

$(document).ready(function(){
//focusblur
jQuery.focusblur = function(focusid) {
var focusblurid = $(focusid);
var defval = focusblurid.val();
focusblurid.attr("disabled",true);

};

/*下面是调用方法*/
$.focusblur("#txt_contract_status");
$.focusblur("#txt_contract_end");

});

</script>