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Example of dynamic addition and deletion of left and right drop-down boxes using JavaScript
Example of dynamic addition and deletion of left and right drop-down boxes using JavaScript
This article introduces an example of dynamic addition and deletion of left and right drop-down boxes using JavaScript. It is very practical. Interested students can refer to this article.
Effect:
1. Html part of the code
<body>
<tablealign="center">
<tr>
<td><selectsize="15"id="left">
<option>左1</option>
<option>左2</option>
<option>左3</option>
<option>左4</option>
<option>左5</option>
<option>左6</option>
<option>左7</option>
<option>左8</option>
<option>左9</option>
<option>左10</option>
</select></td>
<td>
<inputtype="button"value="MoveRight"onclick="moveRight()"><br>
<inputtype="button"value="MoveAllRight"onclick="moveAllright()"/><br>
<inputtype="button"value="MoveLeft"onclick="moveLeft()"><br>
<inputtype="button"value="MoveAllLeft"onclick="moveAllLeft()"><br>
</td>
<td>
<selectsize="15"id="right">
<option>右1</option>
<option>右2</option>
<option>右3</option>
<option>右4</option>
<option>右5</option>
<option>右6</option>
<option>右7</option>
</select>
</td>
<td></td>
</tr>
</table>
</body>2. The JavaScript script code is as follows:
| The code is as follows | |
|
functionmoveRight() { //Get the left side select element node varleftSelectNode = document.getElementById("left"); //Get the child element node array //If the selected index number is -1 , then prompt the user if(leftSelectNode.selectedIndex == -1) { alert("Please select the option that needs to be moved"); return; } //Get the options to be moved varwaitSelection = leftSelectNode.options[leftSelectNode.selectedIndex]; //Get Add the select element node on the right and add varrightSelectNode = document.getElementById("right"); //Add a new node to the right rightSelectNode.appendChild(waitSelection);
}
functionmoveAllright() {//Get the select object varleftSelectNode = document. getElementById("left"); varrightSelectNode = document.getElementById("right");
varoptionsNodes = leftSelectNode.options;
varlength = optionsNodes.length; for(vari = 0; i { rightSelectNode.appendChild(optionsNodes[0] ); } }
functionmoveLeft() { //Get the selection on the left Object varrightSelectNode = document.getElementById("right"); //Prompt if not selected if(rightSelectNode.selectedIndex == -1) { alert("Please select an option"); return; } //Get the option to be moved varwaitMoveNode = rightSelectNode.options[rightSelectNode.selectedIndex]; //Get the select object on the left varleftSelectNode = document.getElementById("left");
//The select object on the left is added to the node leftSelectNode.appendChild(waitMoveNode);
} functionmoveAllLeft() { //Get the select object on the right varrightSelectNode = document.getElementById("right"); varleftSelectNode = document.getElementById("left ");
varlength = rightSelectNode.options.length;
//Traverse its options and add them to the left select for(vari = 0; i { leftSelectNode.appendChild(rightSelectNode.options[0]); } }
| |
3. The simple CSS code is as follows:
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