JavaScript operation select reference code_javascript skills

1. Determine whether there is an Item with Value="paraValue" in the select option. < objSelect.options .length; i ) {                                                                                                                                                    
} 

2. Add an Item to the select option 
function jsAddItemToSelect(objSelect, objItemText, objItemValue) {                                                                                                                           🎜> if (jsSelectIsExitItem(objSelect, objItemValue )) { 🎜> ObjSelect.options.add(varItem) ; ;
alert("Successfully joined"); , objItemValue) {                                                              /Determine whether it exists                                                                                           If (objSelect.options[i] .value == objItemValue) {                                                                                                                                                        🎜> alert("This item does not exist in the selection");


4. Delete the selected item 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 text of value="paraValue" in the select option to "paraText"                                                                                                                                                  🎜> if ( jsSelectIsExitItem(objSelect, objItemValue)) {                                                         == objItemValue) {        
                                                                                                                                                                                                                                                                                                  ; The item does not exist in "); "
} " "
} " " {
//Determine whether it exists
var isExit = false;
for (var i = 0; i < objSelect.options.length; i ) {
if (objS elect.options[i]. text == objItemText) {                                                                                                                                                                                           > if (isExit) { }
}

7. Set the Item with value="paraValue" in the select to be selected
document.all.objSelect.value = objItemValue;

8. Get the current selection of the select The value of the item
var currSelectValue = document.all.objSelect.value;

9. Get the text of the currently selected item of select
var currSelectText = document.all.objSelect.options[document.all .objSelect.selectedIndex].text;

10. Get the Index of the currently selected item of select
var currSelectIndex = document.all.objSelect.selectedIndex;

11. Clear the selected item
document.all.objSelect.options.length = 0;

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<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> <title>javascript select combination_script home_www.jb51.net</title> <select name="select" id="select1"> <option value="1"> </option>This is 1<option value="2"> </option>This is 2</select> <a href="javascript:vtOption()"> </a>Value<a href="javascript:addOption1()"> </a>Increase 1<a href="javascript:addOption2()"> </a>Increase 2<a href="javascript:addOption3()"> </a>Increase 3<a href="javascript:remOption()"> </a>Delete option<a href="javascript:remOptionSelected()"> </a>Delete selected option