Dependency mismatch with Jquery Validate plugin

I am pretty new to Jquery, I am using validation rule against my textbox. The problem is when i mark textbox is mandatory n user doesn't input any value then it doesn't show any validation message. I have associated another validation message for textbox tht the value shu be in range and which works when user provides any input. ``` $.validator.addMethod("requiredRangeFunction", function(value, element) {debugger $.validator.messages["requiredRangeFunction"] = jQuery.format( $(element).attr('ErrorMessage') ? $(element).attr('ErrorMessage') : "Please enter the value between {0} and {1}", $(element).attr('MinValue'), $(element).attr('MaxValue') ); return this.optional(element) || ((value > Number($(element).attr('MinValue')) && (value < Number($(element).attr('MaxValue'))))); }, "Please enter valid value."); ``` issue is with this.optional(element) which returns dependency mismatch when user doesnt provide any input. my textbox can be optional too so i require to call this.optional(element)