JQuery's operation with SELECT option

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Drop-down box:

<select id= "Selectid" >
<option value= "1" >1</option>
<option value= "2" >2</option>
<option value= "3" >3</option>
<option value= "4" >4</option>
<option value= "5" >5</option>
<option value= "6" >6</option>
</select>

Here is the basic operation for the drop-down box:

<script language= "JavaScript" >
$ (document). Ready (function () {
Bind the Drop box change event when the down box changes when calling the Selectchange () method
$ ("#selectID"). Change (function () {Selectchange ();});
})
function Selectchange () {
Gets the Text property value of the drop-down box check item
var SelectText = $ ("#selectID"). Find ("option:selected"). Text ();
alert (SelectText);
Gets the value of the drop-down box for the selected item
var Selectvalue = $ ("#selectID"). Val ();
alert (Selectvalue);
Gets the value of the Index property of the drop-down box selected item
var Selectindex = $ ("#selectID"). Get (0). SelectedIndex;
alert (Selectindex);
Gets the maximum Index property value for the drop-down box
var Selectmaxindex = $ ("#selectID option:last"). attr ("index");
alert (Selectmaxindex);
}

function aa () {
Select the option to set the drop-down box to the Index property of 5
$ ("#selectID"). Get (0). SelectedIndex = 5;
}
function bb () {
The option to set the drop-down box Value property to 4 is selected
$ ("#selectID"). Val (4);
}
function cc () {
Select the option to set the drop-down box Text property to 5
$ ("#selectID option[text=5]"). attr ("Selected", "Selected"); $ ("#yyt option:contains ('5'). attr ("selected", true); }
function dd () {
Add an option at the end of the drop-down box
$ ("#selectID"). Append ("<option value= ' 7 ' >7</option>");
}
function ee () {
Add an option to the top of the dropdown box
$ ("#selectID"). Prepend ("<option value= ' 0 ' >0</option>")
}
function ff () {
Remove the last option from the drop-down box
$ ("#selectID option:last"). Remove ();
}

function Gg () {
Remove drop-down box option with Index property of 1
$ ("#selectID option[index=1]"). Remove ();
}

function hh () {
Remove drop-down box option for Value property 4
$ ("#selectID option[value=4]"). Remove ();
}
Function II () {
Remove drop-down box option for Text property 5
$ ("#selectID option[text=5]"). Remove ();
}
</script>

JQuery's operation with SELECT option