mastersss,
какую структуру приводите такой код и получаите, учите селекторы и основы js.
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<table>
<tr class="row">
<td class="field sub_field field_type-text field_key-field_54ef5eac77c17" data-field_type="text" data-field_key="field_54ef5eac77c17" data-field_name="ball">
<div class="inner">
<div class="acf-input-wrap"><input type="text" id="acf-field-field_54ef5de677c14_0_field_54ef5eac77c17" class="text" name="fields[field_54ef5de677c14][0][field_54ef5eac77c17]" value="55" placeholder=""></div> </div>
</td>
</tr>
<tr class="row">
<td class="field sub_field field_type-text field_key-field_54ef5eac77c17" data-field_type="text" data-field_key="field_54ef5eac77c17" data-field_name="ball">
<div class="inner">
<div class="acf-input-wrap"><input type="text" id="acf-field-field_54ef5de677c14_1_field_54ef5eac77c17" class="text" name="fields[field_54ef5de677c14][1][field_54ef5eac77c17]" value="66" placeholder=""></div> </div>
</td>
</tr>
<tr class="row">
<td class="field sub_field field_type-text field_key-field_54ef5eac77c17" data-field_type="text" data-field_key="field_54ef5eac77c17" data-field_name="ball">
<div class="inner">
<div class="acf-input-wrap"><input type="text" id="acf-field-field_54ef5de677c14_2_field_54ef5eac77c17" class="text" name="fields[field_54ef5de677c14][2][field_54ef5eac77c17]" value="77" placeholder=""></div> </div>
</td>
</tr>
</table>
<script>
var i = document.querySelectorAll('input[id$="54ef5eac77c17"]'), l = i.length-1;
alert(i[l].value);
</script>
</body>
</html>
