JavaScript Operations Select Reference Code _javascript Tips

1. Determine if there is a value= "Paravalue" Item in the Select option
function Jsselectisexititem (Objselect, Objitemvalue) {
var isexit = false;
for (var i = 0; i < objSelect.options.length; i++) {
if (Objselect.options[i].value = = Objitemvalue) {
Isexit = true;
Break
}
}
return isexit;
}

2. Add an item to the Select option
function Jsadditemtoselect (Objselect, Objitemtext, Objitemvalue) {
To determine whether there is
if (Jsselectisexititem (Objselect, Objitemvalue)) {
Alert ("The value of the item already exists");
} else {
var varitem = new Option (Objitemtext, Objitemvalue);
ObjSelect.options.add (Varitem);
Alert ("Join successfully");
}
}

3. Remove an item from the Select option
function Jsremoveitemfromselect (Objselect, Objitemvalue) {
To determine whether there is
if (Jsselectisexititem (Objselect, Objitemvalue)) {
for (var i = 0; i < objSelect.options.length; i++) {
if (Objselect.options[i].value = = Objitemvalue) {
ObjSelect.options.remove (i);
Break
}
}
Alert ("Successful deletion");
} else {
Alert ("The item does not exist in the select");
}
}


4. Delete selected items in select
function Jsremoveselecteditemfromselect (objselect) {
var length = objselect.options.length-1;
for (var i = length; I >= 0; i--) {
if (objselect[i].selected = = True) {
Objselect.options[i] = null;
}
}
}

5. Modify the Select option Value= "Paravalue" text is "Paratext"
function Jsupdateitemtoselect (Objselect, Objitemtext, Objitemvalue) {
To determine whether there is
if (Jsselectisexititem (Objselect, Objitemvalue)) {
for (var i = 0; i < objSelect.options.length; i++) {
if (Objselect.options[i].value = = Objitemvalue) {
Objselect.options[i].text = Objitemtext;
Break
}
}
Alert ("Successful modification");
} else {
Alert ("The item does not exist in the select");
}
}

6. Set the first item of text= "Paratext" in Select to select
function Jsselectitembyvalue (Objselect, Objitemtext) {
To determine whether there is
var isexit = false;
for (var i = 0; i < objSelect.options.length; i++) {
if (Objselect.options[i].text = = Objitemtext) {
Objselect.options[i].selected = true;
Isexit = true;
Break
}
}
Show the results
if (isexit) {
Alert ("Successfully selected");
} else {
Alert ("The item does not exist in the select");
}
}

7. Set the item of value= "Paravalue" in Select to select
Document.all.objSelect.value = Objitemvalue;

8. Value of the current selected item of the Select
var currselectvalue = Document.all.objSelect.value;

9. Gets the text of the currently selected item of select
var currselecttext = Document.all.objselect.options[document.all.objselect.selectedindex].text;

10. Index of the current selected item for select
var currselectindex = Document.all.objSelect.selectedIndex;

11. Empty a Select item
document.all.objSelect.options.length = 0;

The above is collected from the Internet, now look at the contents of the above to do

<! DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 transitional//en" "Http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd "> <ptml xmlns=" http://www.w3.org/1999/xhtml "> <pead> <meta http-equiv=" Content-type "content=" text/html; charset=gb2312 "/> <title>javascript Select Combination _ Yun-Habitat community _www.jb51.net</title> <script language=" JavaScript "type=" Text/javascript > Function vtoption () {var S1=document.getelementbyid ("Select1"); var Sv=s1.options[s1.selectedindex].value; var St=s1.options[s1.selectedindex].text; Alert (sv+ "\ n" +st); function AddOption1 () {var S1=document.getelementbyid ("Select1"); var newop1=new Option; Newop1.value= "3"; Newop1.text= "This is 3"; var newop2=new Option; Newop2.value= "4"; Newop2.text= "This is 4"; S1.add (NEWOP1); S1.add (NEWOP2); function AddOption2 () {var S1=document.getelementbyid ("Select1"); for (Var i=3;i<5;i++) {var newop1=new Option ("This is" +i,i); var newop1=new Option; Newop1.value=i; Newop1.text= "This is"+i; S1.add (NEWOP1); } function AddOption3 () {var S1=document.getelementbyid ("Select1"); s1.options.length=0;//clears the previous option for (Var i=3;i<7;i++) {var newop1=new option ("This is" +i,i); var newop1=new Option; Newop1.value=i; Newop1.text= "This is" +i; S1.add (NEWOP1); } function Remoption () {var S1=document.getelementbyid ("Select1"); for (Var i=s1.options.length;i>=0;i--) {s1.options.remove (i); } function remoptionselected () {var S1=document.getelementbyid ("Select1"); var I=s1.selectedindex; alert (i); S1.options.remove (i); } </script> </pead> <body> <select name= "select" id= "Select1" > <option value= "1" > This is 1&L. T;/option> <option value= "2" > This is 2</option> </select> fetch value    increase 1   increase 2    Add 3   Delete options    Delete selection options </body> </ptml>
[Ctrl + A All SELECT Note: If the need to introduce external JS need to refresh to perform]