JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">
<table id='t1' border='1' class="table-block">
    <tbody>
        <tr class="table-block-header">
            <th class="headcol1">Column1</th>
            <th class="headcol2">+</th>
            <th class="headcol3">Column2</th>
            <th class="table-block-header">10.04.2015</th>
            <th class="table-block-header">11.04.2015</th>
            <th class="table-block-header">12.04.2015</th>
            <th class="table-block-header">13.04.2015</th>
            <th class="table-block-header">14.04.2015</th>
            <th class="table-block-header">15.04.2015</th>
            <th class="table-block-header">16.04.2015</th>
            <th class="table-block-header">17.04.2015</th>
            <th class="table-block-header">18.04.2015</th>
            <th class="table-block-header">19.04.2015</th>
            <th class="table-block-header">20.04.2015</th>
            <th class="table-block-header">21.04.2015</th>
            <th class="table-block-header">22.04.2015</th>
        </tr>
        <tr>
            <td rowspan="2" class="headcol1">
                <input type="checkbox" class="x_selector" value="value1">dummy</td>
            <td class="headcol2">
                <input type="checkbox" class="y_selector" name="VALUE1" value="12345">
            </td>
            <td class="headcol3">text1</td>
            <td>
                <div class="div_up"></div>
                <div class="div_mid">100.00%</div>
                <div class="div_down">0/632</div>
            </td>
            <td>
                <div class="div_up">0.00</div>
                <div class="div_mid">100.00%</div>
                <div class="div_down">0/199</div>
            </td>
            <td>
                <div class="div_up">0.00</div>
                <div class="div_mid">100.00%</div>
                <div class="div_down">0/60</div>
            </td>
            <td>
                <div class="div_up">0.00</div>
                <div...

CSS

.headcol1 {
    position:absolute; 
    width:5em;  
    left:0;
    top:auto;
  }

 .headcol2 {
    position:absolute; 
    width:5em;  
    left:5em;
    top:auto;  
 }

 .headcol3 {
    position:absolute; 
    width:5em; 
    left:10em;
    top:auto;
}

.outer { 
    width: 800px; 
    overflow-x:scroll;  
    margin-left:15em; 
    overflow-y:visible;
    padding-bottom:1px;
}