如何使用javascript设置下拉列表的默认选择索引值 [英] How do i set default selected index value of drop down list using javascript

问题描述

我有公司下拉列表。我想将公司名称设为default.i通过传递公司名称ID从数据库中检索该值。



我有使用了这段代码，但它不能正常工作



我尝试了什么：



var sel = document.getElementById（'Company_ID'）;

sel.selectedIndex = 1;

I have company drop down list.i want to make company name as default.i retrieve that value from database through passing id of company name.

I have used this code,but it's not working

What I have tried:

var sel = document.getElementById('Company_ID');
sel.selectedIndex = 1;

推荐答案

不相信，我测试过你编码。正如我预期的那样，它起作用了。



结论：错误发生在其他地方，而不是你展示的代码。例如，您要使用的 select 元素可能没有 id =Company_ID属性。另一种可能性是：某些其他JavaScript代码错误或甚至词汇错误，因此您的代码片段永远不会被执行。我在代码中遇到词汇错误或异常，脚本将无声地失败，除非你采取特殊措施来揭示问题。



建议：使用JavaScript调试器。您将立即找到问题。

-SA

In disbelieve, I tested you code. Exactly as I expected, it worked.

Conclusion: the bug is elsewhere, not in the code you show. For example, the select element you want to use might not have the attribute id="Company_ID". Another possibility is: some other JavaScript code is wrong or even lexically incorrect, so your fragment of code is never executed. I case of lexical bug or exception in code, the script will fail silently, unless you take special measures to reveal the problem.

Advice: use JavaScript debugger. You will locate the problem in no time.

—SA

这篇关于如何使用javascript设置下拉列表的默认选择索引值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！