Jquery operation Select is simple and convenient. A js plug-in can handle it_jquery

jQuery.fn.size = function()
{
return jQuery(this).get(0).options.length;
}
//Get the index of the selected item
jQuery.fn.getSelectedIndex = function( )
{
return jQuery(this).get(0).selectedIndex;
}
//Get the text of the currently selected item
jQuery.fn.getSelectedText = function()
{
if(this.size() == 0)
{
return "No options in the drop-down box";
}
else
{
var index = this.getSelectedIndex();
return jQuery(this).get(0).options[index].text;
}
}
//Get the value of the currently selected item
jQuery .fn.getSelectedValue = function()
{
if(this.size() == 0)
{
return "No selected value in the drop-down box";
}
else
{
return jQuery(this).val();
}
}
//Set the item with value in select to be selected
jQuery.fn.setSelectedValue = function(value)
{
jQuery(this).get(0).value = value;
}
//Set the first item with text in select to be selected
jQuery .fn.setSelectedText = function(text)
{
var isExist = false;
var count = this.size();
for(var i=0;i{
if(jQuery(this).get(0).options[i].text == text)
{
jQuery(this).get(0).options[i]. selected = true;
isExist = true;
break;
}
}
if(!isExist)
{
alert("The item does not exist in the drop-down box" );
}
}
//Set the selected index item
jQuery.fn.setSelectedIndex = function(index)
{
var count = this.size();
if(index >= count || index < 0)
{
alert("The selected item index is out of range");
}
else
{
jQuery (this).get(0).selectedIndex = index;
}
}
//Determine whether there is an item with value in the select item
jQuery.fn.isExistItem = function(value)
{
var isExist = false;
var count = this.size();
for(var i=0;i{
if(jQuery (this).get(0).options[i].value == value)
{
isExist = true;
break;
}
}
return isExist;
}
//Add an item to the select. The display content is text and the value is value. If the value of the item already exists, it will prompt
jQuery.fn.addOption = function(text,value)
{
if(this.isExistItem(value))
{
alert("The value of the item to be added already exists");
}
else
{
jQuery (this).get(0).options.add(new Option(text,value));
}
}
//Delete the item with value in select, if the item does not exist, Then the prompt
jQuery.fn.removeItem = function(value)
{
if(this.isExistItem(value))
{
var count = this.size();
for(var i=0;i{
if(jQuery(this).get(0).options[i].value == value)
{
jQuery (this).get(0).remove(i);
break;
}
}
}
else
{
alert("The item to be deleted is not Exists!");
}
}
//Delete the item with the specified index in select
jQuery.fn.removeIndex = function(index)
{
var count = this. size();
if(index >= count || index < 0)
{
alert("The index of the item to be deleted is out of range");
}
else
{
jQuery(this).get(0).remove(index);
}
}
//Remove the selected item in select
jQuery.fn.removeSelected = function ()
{
var index = this.getSelectedIndex();
this.removeIndex(index);
}
//Clear all items in select
jQuery.fn. clearAll = function()
{
jQuery(this).get(0).options.length = 0;
}