Jquery sets the default selection for a drop-down list (select) based on value values

Method One:

$ ("#selIndustyType option[value= ' 1 ']"). attr ("Selected", "Selected");

View Code

Method Two:

<script type= "Text/javascript" >functionChange (ObjID, newvalue) {varobj = $ ("#" +ObjID); if(!obj) {Alert ("Object is empty, execution returns!" "); return; }            varoptions = obj.find ("option")); Options.each (function(i) {if($( This). Text () = = =newvalue) {                    $( This). attr ("Selected",true); --Also available obj.get (0). SelectedIndex =i; substitution}}); }    </script>

View CodeNote: 1, the object is equal line judgment, use = = = instead of = =, the JS engine executes two equal symbols, the type conversion is done automatically. Compare the "1" ==1 with "1" ===1 to know the result 2, the above code needs to refer to the JQuery library. I am out, only recently know the strength of the library 3, learn to use $,. Find (),. attr use 4, use alternative Obj.get (0). SelectedIndex = i; , Obj.get (0) is not fully understood, why does it have the SelectedIndex attribute?

Jquery sets the default selection for a drop-down list (select) based on value values