JavaScript

if(this.value == this.defaultValue){
    alert("Before this.select();"); // If you wont see this alert this.value does not equal this.defaultValue
                                    // Could it be that you wanted to check for unequal i.e. != ?
    this.select();
}

$(document).ready(function()
{
     $("input:text").focus(function()
     {
     $(this).select();
     }
     );
 });

document.getElementById("someDiv").style.width = "700px";

<script type="text/javascript">

var ScreenWidth=screen.width;
var ScreenHeight=screen.height;

if(ScreenWidth=="1280"&&ScreenHeight=="1024")
{document.getElementById("body").style.width = "10%";
    }

</script>

<script type="text/javascript">

var ScreenWidth=screen.width;
var ScreenHeight=screen.height;

if(ScreenWidth=="1280"&&ScreenHeight=="1024")
{document.getElementById("outer").style.width = "10%";
    }

</script>

myHeight = window.screen.height; //this gives screen height
myWidth = window.screen.width; //this gives screen widht

.class1024 {
color : "green";
}
.class800 {
color : "blue";
}

if(myWidth == 1024) {
  elem.className='class1024'; 
}
else if (myWidth == 800) {
  elem.className='class800'; 
}