setTimeout() can be used to call a function after a specified time, and to auto-call a function multiple times, if it is added inside it. But, setTimeout() causes javascript to use the global scope, and this can be a problem when it is used inside a class, because it cannot be used with the special word this.
setTimeout() not works as we expect.
<h4>Example this in setTimeout()</h4>
<div id="swprop"></div>
<script>
// defines a class function
class className {
constructor(){
this.prop = 0;
}
// method
metName() {
document.getElementById('swprop').innerHTML = this.prop; // shows prop value in #swprop
// adds one unit to prop to each call, and auto-calls this function every 0.5 sec., till prop reaches 10
this.prop++;
if(this.prop < 10) setTimeout('this.metName()', 500);
}
}
// creates an object of className, and accesses metName()
var objTest = new className();
objTest.metName();
</script>
setTimeout() is scoping via itself.The solution is to apply the bind(val) method, which has its this keyword set to the provided value (val).
- So, in setTimeout() use this syntax:
<h4>Example bind() method in setTimeout()</h4>
<div id="swprop"></div>
<script>
// defines a class function
class className {
constructor(){
this.prop = 0;
}
// method
metName() {
document.getElementById('swprop').innerHTML = this.prop; // shows prop value in #swprop
// adds one unit to prop to each call, and auto-calls this function every 0.5 sec., till prop reaches 10
this.prop++;
if(this.prop < 10) setTimeout(this.metName.bind(this), 500);
}
}
// creates an object of className, and accesses metName()
var objTest = new className();
objTest.metName();
</script>
<embed src="flash_game.swf" width="450" height="350" />
#id:first-line {
font-weight: bold;
color: blue;
}var url = window.location; alert(url);
$homepage = file_get_contents("http://coursesweb.net/");
echo $homepage;