before submit event in jqgrid

I hav got 2 jquery date picker fields in my form.One for start date and another for end date. i want to check whether start date is less than end date . for that i used beforesubmit event5 of jqgrid but how to check it using javascript and am using php as server si开发者_如何学JAVAde lang... please answer me as am beginner to jqgrid

You can also check it in PHP file which you define in your editurl in the Grid. If it goes wrong just return the error and check for the returning error in the AfterSubmit function in Add Options in your jqGrid.