Convert string to number and add one

Solution 1:

Assuming you are correct and your id is a proper number (without any other text), you should parse the id and then add one to it:

var currentPage = parseInt($(this).attr('id'), 10);
++currentPage;

doSomething(currentPage);

Solution 2:

Have you tried flip-flopping it a bit?

var newcurrentpageTemp = parseInt($(this).attr("id"));
newcurrentpageTemp++;
alert(newcurrentpageTemp));

Solution 3:

I believe you should add 1 after passing it to parseInt

$('.load_more').live("click",function() { //When user clicks
          var newcurrentpageTemp = parseInt($(this).attr("id")) + 1;   
          alert(newcurrentpageTemp);
          dosomething();
      });

http://jsfiddle.net/GfqMM/

Solution 4:

$('.load_more').live("click",function() { //When user clicks
          var newcurrentpageTemp = parseInt($(this).attr("id")) + 1
          dosomething(newcurrentpageTemp );
      });

http://jsfiddle.net/GfqMM/