javascript - how to retain drop down selected values after form submitted? -

how retain drop down selected values after form submitted? have form submit via onchange problem when select value drop down form submitted drop down values struck on select option

javascript

<script> function getdropdownvalue(){ var e = document.getelementbyid("size"); var struser = e.options[e.selectedindex].value; } </script> 

drop down select

<form name="size" id="size"> <select style="background-color:#ccc" name="size[]"  id="size"  onchange="this.form.submit();getdropdownvalue();" > <option value="">select</option> <option value="small">small</option> <option value="medium">medium</option> <option value="large">large</option> <option value="xl">xl</option> </select></form> 

you want run getdropdownvalue(); before submitting form:

<select style="background-color:#ccc" name="size[]" id="size" onchange="getdropdownvalue();this.form.submit();" >

to make sure drop-down value retained, submit form invisible iframe. allows form submitted without refreshing page:

<form target="invisible">...</form> <iframe name="invisible" style="display: none"></iframe>