清空select的项
Html 代码
- 1. // document.all.objSelect.options.length = 0;
如果留下第一行的话就是
Html 代码
- document.all.objSelect.options.length = 1;
判断select选项中 是否存在Value="paraValue"的Item
Js 代码
- 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;
- }
向select选项中 加入一个Item
Js 代码
- 1. function jsAddItemToSelect(objSelect,objItemText,objItemValue)
- 2. {
- 3. // 判断是否存在
- 4. if(jsSelectIsExitItem(objSelect,objItemValue))
- 5. {
- 6. alert(" 该Item的Value值已经存在");
- 7. }
- 8. else
- 9. {
- 10. var varItem = new Option(objItemText,objItemValue);
- 11. // objSelect.options[objSelect.options.length] = varItem;
- 12. objSelect.options.add(varItem);
- 13. alert(" 成功加入");
- 14. }
- 15. }
从select选项中 删除一个Item
Js 代码
- 1. function jsRemoveItemFromSelect(objSelect,objItemValue)
- 2. {
- 3. // 判断是否存在
- 4. if(jsSelectIsExitItem(objSelect,objItemValue))
- 5. {
- 6. for(var i=0;i<objSelect.options.length;i++)
- 7. {
- 8. if(objSelect.options[i].value == objItemValue)
- 9. {
- 10. objSelect.options.remove(i);
- 11. break;
- 12. }
- 13. }
- 14. alert(" 成功删除");
- 15. }
- 16. else
- 17. {
- 18. alert(" 该select中 不存在该项");
- 19. }
- 20. }
修改select选项中 value="paraValue"的text为"paraText"
Js代码
- 1. function jsUpdateItemToSelect(objSelect,objItemText,objItemValue)
- 2. {
- 3. // 判断是否存在
- 4. if(jsSelectIsExitItem(objSelect,objItemValue))
- 5. {
- 6. for(var i=0;i<objSelect.options.length;i++)
- 7. {
- 8. if(objSelect.options[i].value == objItemValue)
- 9. {
- 10. objSelect.options[i].text = objItemText;
- 11. break;
- 12. }
- 13. } alert(" 成功修改");
- 14. }
- 15. else
- 16. {
- 17. alert(" 该select中 不存在该项");
- 18. }
- 19. }
设置select中text="paraText"的第一个Item为选中
Js 代码
- 1. function jsSelectItemByValue(objSelect,objItemText)
- 2. {
- 3. // 判断是否存在
- 4. var isExit = false;
- 5. for(var i=0;i<objSelect.options.length;i++)
- 6. {
- 7. if(objSelect.options[i].text == objItemText)
- 8. {
- 9. objSelect.options[i].selected = true;
- 10. isExit = true;
- 11. break;
- 12. }
- 13. }
- 14. //Show 出结果
- 15. if(isExit)
- 16. {
- 17. alert(" 成功选中");
- 18. }
- 19. else
- 20. {
- 21. alert(" 该select中 不存在该项");
- 22. }
- 23. }
设置select中value="paraValue"的Item为选中
得到select的当前选中项的value
得到select的当前选中项的text
得到select的当前选中项的Index
Js 代码
- //document.all.objSelect.value = objItemValue;
//document.all.objSelect.value = objItemValue;
得到select的当前选中项的value
Js 代码
- //var currSelectValue = document.all.objSelect.value;
//var currSelectValue = document.all.objSelect.value;
得到select的当前选中项的text
Js 代码
- //var currSelectText = document.all.objSelect.options[document.all.objSelect.selectedIndex].text;
//var currSelectText = document.all.objSelect.options[document.all.objSelect.selectedIndex].text;
得到select的当前选中项的Index
Js 代码
- //var currSelectIndex = document.all.objSelect.selectedIndex;
Html 代码
- < html >
- < head >
- < title > js 控制select增删改,选中,清空, 判断控件是否存在 </ title >
- < meta name = "keywords" content = "javascript select options text value add modify delete set" >
- < meta name = "description" content = "javascript select options text value add modify delete set" >
- < script language = "javascript" >
- <!--
- function watch_ini() { // 初始
- for(var i = 0 ; i < arguments.length ; i++){
- var oOption = new Option(arguments[i],arguments[i]);
- document.getElementById("MySelect")[i]=oOption;
- }
- }
- function watch_add(f) { // 增加
- var oOption = new Option(f.word.value,f.word.value);
- f.keywords[f.keywords.length]=oOption;
- }
- function watch_sel(f) { // 编辑
- f f.word.value = f.keywords[f.keywords.selectedIndex].text;
- }
- function watch_mod(f) { // 修改
- f.keywords[f.keywords.selectedIndex].text = f .word.value;
- }
- function watch_del(f) { // 删除
- f.keywords.remove(f.keywords.selectedIndex);
- }
- function watch_set(f) { // 保存
- var set = "" ;
- for(var i = 0 ; i < f.keywords.length ; i++){
- set += f.keywords[i].text + ";";
- }
- confirm(set);
- }
- //-->
- </ script >
- </ head >
- < body >
- < form name = "watch" method = "post" action = "" >
- < select id = "MySelect" name = "keywords" size = "10" onchange = "watch_sel(this.form)" > </ select > < br >
- < script language = "javascript" >
- <!--
- watch_ini(" 黑","色","头","发","紫","色","头","发"); // 初始关键词
- //-->
- </ script >
- < input type = "text" name = "word" /> < br />
- < input type = "button" value = " 增加" onclick = "watch_add(this.form);" />
- < input type = "button" value = " 修改" onclick = "watch_mod(this.form);" />
- < input type = "button" value = " 删除" onclick = "watch_del(this.form);" />
- < input type = "button" value = " 保存" onclick = "watch_set(this.form);" />
- </ form >
- </ body >
- </ html >