JavaScript sets the default option for select

JavaScript sets the default option for select.

can use Selectobj.options[index].selected=true; To set

Selectobj the object of the Drop-down box

Subscript for index Default item

If you cannot determine the default subscript for the number of options, you can use the following method.

This method returns the subscript for the option after the default option is set.

Sets the default option for select and gets the subscript for the option.
Parameter 1: The object of the Drop-down box, parameter 2: The text content of the option
function setselected (selectobj,optionstext) {
for (Var i=0;i<selectobj.options.length;i++) {
if (Selectobj.options[i].text==optionstext) {
Selectobj.options[i].selected=true;
return i;
}
}
}

Of course, the method can also be modified to a selected value to determine the default option.

Example:

<select id= "seletest" Name= "" >
<option value= "0" >a</option>
<option value= "1" >b</option>
<option value= "2" >c</option>
<option value= "3" >d</option>
<option value= "4" >e</option>
</select>

<script>
var Selobj=document.getelementbyid (' Seletest ');
var s2=setselected (selobj, ' d ')
Alert (' s2= ' +s2);
</script>