When dropdownlist is triggered, a JS error is reported, while updatepanel is refreshing. The frontend JS gets the dynamic value in the background.

1. When dropdownlist is triggered, a JS error is returned. If no error is returned for the first loading, but an error is returned when selecting this option,

There are two judgments:

1. There is a problem with the data bound to dropdownlist ..

2. When processing data in the dropdownlist, there is a problem with the method in the indexchange event.

 

2. Updatepanel is refreshing.

Put the parts that require no refreshing updates into updatepanel. If you need to assign values to hidden fields, you must also put them in updatepanel.

 

3. the foreground JS gets the dynamic value of the day after tomorrow.

1. Simplest method <% = backend method or public field %>

2. If not? Place a hidden field under the trigger event control. Then, the background value is assigned to the hidden domain. The foreground document. getelementbyid ("hdfvalue"). Value