i have this below table.and i want to change a specific column width=>by changing its default width.previously i have done that.but now on this below table its not working for me.i dont know why.
i want to change those column where i add width:400px; i know css expert can help me about this.please help.i have a very little knowledge in css.
.namex {
overflow: scroll;
}
<div class="namex">
<table class="table">
<tr>
<th>
Full Name
</th>
<th>
First Name
</th>
<th>
Last Name
</th>
<th>
Profile Pic
</th>
<th style="width:400px;">
Currently Assigned Courses
</th>
<th width="200px">
Currently Assigned Batches
</th>
<th>
Company Name
</th>
<th>
City
</th>
<th>
Phone Number
</th>
<th>
Email Address
</th>
<th>
Zip Code
</th>
<th>
User Nationality
</th>
<th>
Gender
</th>
<th>
Religion
</th>
<th>
Blood Group
</th>
<th>
Date Of Birth
</th>
<th>
User Activation Date
</th>
<th>
User Current Status
</th>
<th></th>
</tr>
<tr>
<td>
md.amjad hossain
</td>
<td>
md.amjad
</td>
<td>
hossain
</td>
<td>
<img src="/Content/img/tsms/default/owner.jpg" height="80" width="80" style="border-radius:2px;" />
</td>
<td>
<select onchange="alert(this.value)" class="form-control input-lg">
<option value="CCNA Security">CCNA Security</option>
<option value="Oracle Database 12c">Oracle Database 12c</option>
</select>
</td>
<td>
<select onchange="alert(this.value)" class="form-control input-lg">
<option value="CCNA Security-1">CCNA Security-1</option>
<option value="Oracle Database 12c-1">Oracle Database 12c-1</option>
</select>
</td>
<td>
aiub
</td>
<td>
dhaka
</td>
<td>
1830954149
</td>
<td>
<a href="mailto:[email protected]">[email protected]</a>
</td>
<td>
1362
</td>
<td>
bangladeshi
</td>
<td>
male
</td>
<td>
islam
</td>
<td>
o+
</td>
<td>
2/25/1995
</td>
<td>
5/8/2017
</td>
<td>
Active
</td>
<td>
<a href="/Students/Edit/2">Edit</a> |
<a href="/Students/Details/2">Details</a> |
<a href="/Students/Delete/2">Delete</a>
</td>
</tr>
</table>
</div>
in my case its look like ---
[![Pic of my table][1]][1]
[1]: https://i.sstatic.net/d8Dr0.png
look
<th style="width:400px;">
Currently Assigned Courses
</th>
<th width="200px">
Currently Assigned Batches
</th>
is not working after applying width.its still look like 0px.
thats my problem.
<th style="width:400px;">
Currently Assigned Courses
</th>
<th width="200px">
Currently Assigned Batches
</th>
is not working after applying width.its still look like 0px. thats my problem.

Currently Assigned CoursesandCurrently Assigned Batches, which one is not rendering properly in your code?<td>and<th>are by defaultdisplay: table-cell(UserAgent styles). If you change them to for exampledisplay: block, the width will take effectwidthattribute of<th>is not supported in HTML5. Use CSS instead -<th style="width:400px;">is fine