JS operation select drop-down box dynamic changes (create/delete/get)_javascript skills

1. Dynamically create select

Copy code The code is as follows:

function createSelect(){
var mySelect = document.createElement_x("select");
mySelect.id = "mySelect";
document.body.appendChild(mySelect);
}

2 .Add option option

Copy code The code is as follows:

function addOption(){
//Find objects based on id,
var obj=document.getElementByIdx_x('mySelect');
//Add an option
obj.add(new Option("text","value"));
}

3. Delete all options option

Copy code The code is as follows:

function removeAll(){
var obj=document.getElementByIdx_x('mySelect');
obj.options.length=0;
}

4. Delete an option option

Copy code The code is as follows:

function removeOne(){
var obj=document.getElementByIdx_x('mySelect');
//index, to delete the serial number of the option, here take the serial number of the currently selected option
var index=obj.selectedIndex;
obj. options.remove(index);
}

5. Get the value of option option

Copy code The code is as follows:

var obj=document.getElementByIdx_x('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options[index].value;

6. Get the text of option option

Copy code The code is as follows:

var obj=document.getElementByIdx_x('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options[index].text;

7. Modify option option

Copy code The code is as follows:

var obj=document.getElementByIdx_x('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options[index]=new Option("new text","new value");

8. Delete select

Copy code The code is as follows:

function removeSelect(){
var mySelect = document.getElementByIdx_x("mySelect");
mySelect. parentNode.removeChild(mySelect);
}