Detailed explanation of single-select and multiple-select usage of select tag in HTML_HTML/Xhtml

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Detailed explanation of single-select and multiple-select usage of select tag in HTML_HTML/Xhtml_Web page production

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May 16, 2016 pm 04:37 PM

htmlselect tagSingle choiceMultiple choice

The select element creates single-select or multiple-select menus. When the form is submitted, the browser submits the selected items, or collects multiple comma-separated options, combines them into a single parameter list, and includes the name attribute when submitting the

Where, The option> tag can be omitted and used in the page

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The code is as follows:

> ;

2. The Select element can also be used for multiple selections, see the following code:

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The code is as follows:

//With the multiple attribute, you can select multiple times

//The following is the case where the size attribute is set. If size = 3, then three pieces of data will be displayed. Note that multiple selections are not allowed.

3. All common operations involved in the multi-select Select component:

1. Determine the select option Whether there is an Item with the specified value in

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The code is as follows: @param objSelectId The id of the target select component to be verified

@param objItemValue The value to be verified for existence

function isSelectItemExit(objSelectId,objItemValue) {

var objSelect = document.getElementById(objSelectId);
var isExit = false;
if (null != objSelect && typeof(objSelect) != "undefined") {
for(var i=0;iif( objSelect.options[i].value == objItemValue) {
isExit = true;
break;
}
}
}
return isExit;
}

2. Add an Item to the select option

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The code is as follows:

@param objSelectId The id of the target select component to be added to the item
@param objItemText The content of the item to be added
@param objItemValue The value of the item to be added
function addOneItemToSelect(objSelectId ,objItemText,objItemValue) {
var objSelect = document.getElementById(objSelectId);
if (null != objSelect && typeof(objSelect) != "undefined") {
//Determine whether the value is item already exists in the select
if(isSelectItemExit(objSelectId,objItemValue)) {
$.messager.alert('Prompt message','The option with this value already exists!','info');
} else {
var varItem = new Option(objItemText,objItemValue);
objSelect.options.add(varItem);
}
}
}

3. Delete the selected item from the select option, supporting multiple selection and multiple deletion

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The code is as follows:

@param objSelectId The target select component id to be deleted
function removeSelectItemsFromSelect(objSelectId) {
var objSelect = document.getElementById(objSelectId);
var delNum = 0;
if (null != objSelect && typeof(objSelect) != "undefined") {
for(var i=0;iif(objSelect .options[i].selected) {
objSelect.options.remove(i);
delNum = delNum 1;
i = i - 1;
}
}
if (delNum $.messager.alert('Message', 'Please select the option you want to delete!', 'info');
} else {
$.messager .alert('prompt message',''delNum' options were successfully deleted!','info');
}
}
}

4. From select Delete an Item according to the specified value in the option

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The code is as follows:

@param objSelectId The id of the target select component to be verified
@param objItemValue The value to be verified for existence
function removeItemFromSelectByItemValue(objSelectId,objItemValue) {
var objSelect = document.getElementById(objSelectId);
if (null != objSelect && typeof(objSelect) != "undefined") {
//Determine whether it exists
if(isSelectItemExit(objSelect,objItemValue)) {
for(var i=0;i< ;objSelect.options.length;i ) {
if(objSelect.options[i].value == objItemValue) {
objSelect.options.remove(i);
break;
}
}
$.messager.alert('Message','Deleted successfully!','info');
} else {
$.messager.alert('Message','No There are options with specified values!','info');
}
}
}

5. Clear all options in select

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The code is as follows:

@param objSelectId The target select component id to be cleared
function clearSelect( objSelectId) {
var objSelect = document.getElementById(objSelectId);
if (null != objSelect && typeof(objSelect) != "undefined") {
for(var i=0;iobjSelect.options.remove(i);
}
}
}

6. Get all items in select, and Assemble all the values into a string, separated by commas

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The code is as follows:

@param objSelectId target select component id
@return the values of all items in select, separated by commas
function getAllItemValuesByString(objSelectId) {
var selectItemsValuesStr = "";
var objSelect = document.getElementById(objSelectId);
if (null != objSelect && typeof(objSelect) != "undefined") {
var length = objSelect.options.length
for(var i = 0; i if (0 == i) {
selectItemsValuesStr = objSelect.options[i].value;
} else {
selectItemsValuesStr = selectItemsValuesStr "," objSelect.options[i].value;
}
}
}
return selectItemsValuesStr;
}

7. Move all selected options in one select to another select

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The code is as follows :

@param fromObjSelectId The original select component id of the moved item
@param toObjectSelectId The target select component id that the moved item will enter
function moveAllSelectedToAnotherSelectObject(fromObjSelectId, toObjectSelectId) {
var objSelect = document. getElementById(fromObjSelectId);
var delNum = 0;
if (null != objSelect && typeof(objSelect) != "undefined") {
for(var i=0;iif(objSelect.options[i].selected) {
addOneItemToSelect(toObjectSelectId,objSelect.options[i].text,objSelect.options[i].value)
objSelect.options.remove(i);
i = i - 1;
}
}
}
}

8. Move all options to another select

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The code is as follows:

@param fromObjSelectId The original select component id of the moved item
@param toObjectSelectId The target select component id that the moved item will enter
function moveAllToAnotherSelectObject(fromObjSelectId, toObjectSelectId) {
var objSelect = document.getElementById(fromObjSelectId);
if (null != objSelect) {
for(var i=0;iaddOneItemToSelect(toObjectSelectId,objSelect.options[i].text ,objSelect.options[i].value)
objSelect.options.remove(i);
i = i - 1;
}
}
}

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