清空select的项
- // document.all.objSelect.options.length = 0;
// document.all.objSelect.options.length = 0;
如果留下第一行的话就是
- // document.all.objSelect.options.length = 1;
// document.all.objSelect.options.length = 1;
判断select选项中 是否存在Value="paraValue"的Item - 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;
- }
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 - function jsAddItemToSelect(objSelect,objItemText,objItemValue)
- {
-
- if(jsSelectIsExitItem(objSelect,objItemValue))
- {
- alert("该Item的Value值已经存在");
- }
- else
- {
- var varItem = new Option(objItemText,objItemValue);
-
- objSelect.options.add(varItem);
- alert("成功加入");
- }
- }
function jsAddItemToSelect(objSelect,objItemText,objItemValue){//判断是否存在if(jsSelectIsExitItem(objSelect,objItemValue)){alert("该Item的Value值已经存在");}else{var varItem = new Option(objItemText,objItemValue);// objSelect.options[objSelect.options.length] = varItem;objSelect.options.add(varItem);alert("成功加入");}}
从select选项中 删除一个Item - function jsRemoveItemFromSelect(objSelect,objItemValue)
- {
-
- 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("成功删除");
- }
- else
- {
- alert("该select中 不存在该项");
- }
- }
function jsRemoveItemFromSelect(objSelect,objItemValue){//判断是否存在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("成功删除");}else{alert("该select中 不存在该项");}}
修改select选项中 value="paraValue"的text为"paraText" - function jsUpdateItemToSelect(objSelect,objItemText,objItemValue)
- {
-
- 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("成功修改");
- }
- else
- {
- alert("该select中 不存在该项");
- }
- }
function jsUpdateItemToSelect(objSelect,objItemText,objItemValue){//判断是否存在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("成功修改");}else{alert("该select中 不存在该项");}}
设置select中text="paraText"的第一个Item为选中 - function jsSelectItemByValue(objSelect,objItemText)
- {
-
- 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;
- }
- }
-
- if(isExit)
- {
- alert("成功选中");
- }
- else
- {
- alert("该select中 不存在该项");
- }
- }
function jsSelectItemByValue(objSelect,objItemText){//判断是否存在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出结果if(isExit){alert("成功选中");}else{alert("该select中 不存在该项");}}
设置select中value="paraValue"的Item为选中 //document.all.objSelect.value = objItemValue;
得到select的当前选中项的value //var currSelectValue = document.all.objSelect.value;
得到select的当前选中项的text //var currSelectText = document.all.objSelect.options[document.all.objSelect.selectedIndex].text;
得到select的当前选中项的Index //var currSelectIndex = document.all.objSelect.selectedIndex;
完整例子
- <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
- <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
- ff.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>