Question

I’m saw this line a lot but can’t find an answer:

$.jgrid.useJSON = true;

What is the purpose?

Answer 1

Typically I include jqGrid in the following way

<link rel="stylesheet" type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/themes/redmond/jquery-ui.css" />
<link rel="stylesheet" type="text/css" href="http://www.ok-soft-gmbh.com/jqGrid/jquery.jqGrid-4.4.1/css/ui.jqgrid.css" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/jquery-ui.min.js"></script>
<script type="text/javascript" src="http://www.ok-soft-gmbh.com/jqGrid/jquery.jqGrid-4.4.1/js/i18n/grid.locale-en.js"></script>
<script type="text/javascript">
    $.jgrid.no_legacy_api = true;
    $.jgrid.useJSON = true;
</script>
<script type="text/javascript" src="http://www.ok-soft-gmbh.com/jqGrid/jquery.jqGrid-4.4.1/js/jquery.jqGrid.min.js"></script>
<script type="text/javascript" src="http://www.ok-soft-gmbh.com/jqGrid/json2.js"></script>

So one should first include grid.locale-en.js which defines $.jgrid, then you can set $.jgrid.useJSON and $.jgrid.no_legacy_api and the later implementation of jqGrid in jquery.jqGrid.min.js will use the settings.

The option $.jgrid.useJSON will be used in $.jgrid.parse for parsing JSON strings either with JSON.parse or with eval.

To be exact the method $.jgrid.parse will be used not so frequently. Mostly two cases are relevant:

1. parsing of input datastr in case if the value of datastr has “string” type and datatype: "jsonstring"
2. parsing of postData.filters (the filter parameter used with local datatype and for advanced searching)
3. parsing JSON response from the server for subgrids in case of subgridtype: "json"
4. inside of jqGridImport method implementation

So the usage of $.jgrid.useJSON = true; is recommended, but it will influence the performance of your program probably not really because the most important cases of JSON parsing will be made typically by jQuery internally (typically by jQuery.ajax) and not by jqGrid code.