html和echo语句中的字符串连接

Question

So I have this line of code in a php file:

echo "<a class='button' onclick=report('$row[id]')></a>";

I'd like to add an id to the line, so I tried this:

echo "<a class='button' id='"report".$row[id]' onclick=changeColor('$row[id]')></a>";

and in my javascript file

document.getElementById('report'+id).style.color('blue');

but I keep getting errors in javascript

cannot read property 'style' of null,

because I'm doing something wrong with the concatenation. I'm trying to get the id to be something like "report100" by concatenating it with $row[id] and then in the javascript file, change it's font color. I've tried other variations, but I just seem to get it right.

Answer 1

try like this.

echo "<a class='button' id='report".$row['id']."' onclick=changeColor(".$row['id'].")></a>";

UPDATE :

To concatenate a string and variable together, use the string concatenation operator . (a dot).

As well it is depend on how you start the string

Starting the string with '' (single quotes) will be

echo '<a class="button" id="report'.$row['id'].'">';

Starting the string with "" (double quotes) will be

echo "<a class='button' id='report'".$row['id'].">";