Gurus, I have a situation that I need to assign the textbox value based on dropdown list’s selected value using JavaScript Here Is my javascript function <script language="javascript"> function MakeRowDirty(kp,id){ var kpVal = kp.options[kp.selectedIndex].value; if (kpVal==-1) { document.getElementById(id).value = '0'; } else { document.getElementById(id).value = '1'; } } </script> This is how I am calling function Dim dirty As New TextBox dirty = e.Item.FindControl("txtDirty") Dim kp As New MIDKeyPressDDL.KeyPressDDL // this is dropdown kp = e.Item.FindControl("kpCodes") kp.AfterKeypressOnChange = "MakeRowDirty(this,'" & dirty.UniqueID & "'); return showHideRiskFactors(this);" it throws error : script5007 unable to set property 'value' of undefined or null reference--- else { document.getElementById(id).value = '1'; // here I am getting ...

Go to the complete details ...