Often times, when dealing with this using PHP, I’ll change the spaces to underscores for all processing. Only when it is displayed, I’ll change the underscores back to spaces.
In your case, you want to display it with a space (within a text box), so you do need it to be a space.
Your text box has no “name” … you might need a name.
Here is an example line from an imp tutorial … <input type='text' name='firstname' value='" + fname + @"'>
Also, the value has small quotes around double quotes. Try it like that.