javascript - Prevent text entry in textbox unless checkbox is checked -

i'm trying prevent text being entered in textbox unless checkbox corresponds textbox checked.

// validate "other" textbox var isother = document.getelementbyid("isother"); isother.addeventlistener("input", function (evt) {      // checkbox must checked before data can entered textbox      if (isother.checked) {           document.getelementbyid("other").disabled = false;      } else {           document.getelementbyid("other").disabled = true;      } }); 

do not use disabled. instead use readonly. during document load, uncheck , disable inputs:

<input type="checkbox" id="isother" /> <input type="text" id="other" readonly /> 

and use script.

// validate "other" textbox var isother = document.getelementbyid("isother"); var other = document.getelementbyid("other"); isother.addeventlistener("click", function () {     other.readonly = !isother.checked; }); other.addeventlistener("focus", function (evt) {      // checkbox must checked before data can entered textbox     other.readonly = !isother.checked; }); 

longer version.

// validate "other" textbox var isother = document.getelementbyid("isother"); var other = document.getelementbyid("other"); isother.addeventlistener("click", function () {      if (isother.checked) {           other.readonly = false;      } else {           other.readonly = true;      } }); other.addeventlistener("focus", function (evt) {      // checkbox must checked before data can entered textbox      if (isother.checked) {           this.readonly = false;      } else {           this.readonly = true;      } }); 

fiddle: http://jsfiddle.net/praveenscience/zqqz9/1/

fiddle: http://jsfiddle.net/praveenscience/zqqz9/