Newbie question

[gpet]

hi everyone
I am new in php so forgive me if the question is to easy.

How a textbox that has not a default value can take only two values 0 or 1 everytime that i submit a page.First time one second 0 and so on.

Thanks all in advanced

Sorry if my english are bad

 

[jpadie]

textboxes (the textarea element or the <input type="text"> element) are designed for free text input. you can contrain them with javascript but then you are using them outside of their design parameters.

conversely, to provide a boolean switch, html provides you with the checkbox control.

the problem with a checkbox control is that its value is only submitted if it is checked. so your server code needs to check whether the checkbox is actually submitted and assign a value if not.

for this form, for example

<form method="post" action="$_SERVER['PHP_SELF']">
 <input type="checkbox" name="blnSwitch" /> Click for true<br/>
 <input type="submit" name="submit" value="submit"/>
</form>

you would receive the script as follows

if (isset($_POST['submit'])){ //form has been submitted
  $checkbox = isset($_POST['blnSwitch']) ? 1 : 0;
  echo "the checkbox value was $checkbox";
}

alternatively you could use javascript to create an 'advanced checkbox'

<script>
function advCbox(ctrl){
 var a_ctrl = document.getElementById('adv' + ctrl.name);
 a_ctrl.value = ctrl.checked ? '1' : '0';
}
</script>
<form method="post" action="$_SERVER['PHP_SELF']">
 <input type="checkbox" name="_blnSwitch" onchange='advCbox(this);' /> Click for true<br/>
 <input type="hidden" name="blnSwitch" id="adv_blnSwitch" value="0"/>
 <input type="submit" name="submit" value="submit"/>
</form>

your receiving code would then just use the value of $_POST['blnSwitch']

given that not all users have javascript enabled, my preference would always be for the server side validation solution (the first). If you want to use a full javascript validation solution then this is outside of the scope of this forum and you should take the question to our javascript brethren.