grid中使用Ext.selection.CheckboxModel，如何让状态为1的不能选，求指教。。。

{header: 'Status', flex: 1, sortable: true,id:'status_id', dataIndex: 'status',
renderer: function(value, cellmeta, record, rowIndex, columnIndex, store){
if(value==1){
var str ="<input type='checkbox' disable='false' />";
return str;
}else{
var str ="<input type='checkbox' disable='true' />";
return str;
}
}},

renderer:function(value){ if(value){return "<input type='checkbox' onchange='JavaScript:if(this.checked) {this.checked = false;} else{this.checked = true;}' checked />";}else {return "<input type='checkbox' onchange='JavaScript:if(this.checked) {this.checked = false;} else{this.checked = true;}' />";} }